feat(stageshow): enable validated UI showcase workflow

THIRD_PARTY_NOTICES.md

@@ -12,3 +12,16 @@ Stack owns command mappings and package metadata, not the upstream skill impleme
 | Stewdio blank-page skill | StewdioAI/blank-page | `cd42b37fa7cd0a5550e51f45cc8f82f63377b98c` | MIT |
 
 Stack-Codex is Stack-owned repository content, bundled under `packages/stack-codex/content` so a GitHub clone contains the complete eight-skill package. Its package pin, `483015638591618e884d4c21f1fa037b645bb872e33acf063fa7a5f802c80df3`, is a deterministic SHA-256 digest over sorted relative paths and exact file bytes. It is not an external upstream and does not appear in the third-party table above.
+
+## Stageshow
+
+The pinned integration in `skills/imported/benjitaylor/stageshow` imports
+Benji Taylor's Stageshow 0.1.0 from `benjitaylor/skills` at
+`802057409787133703c56001080169e347305572`. Its MIT license, upstream notices,
+retained artwork licenses/source records and CC0 photograph attribution remain
+with the import. The MIT license does not cover app-bundle artwork or grant
+trademark rights. App-bundle icons and five official-only brand SVGs are omitted;
+copied phone glyph paths are replaced with independently authored generic
+geometry. `source.json` and `STACK-REVIEW.md` record the exact subset, modifications
+and representative isolated runtime validation. Local compiler/installer receipts
+record managed-runtime availability; dependencies are not bundled into exports.

artifacts/audits/phase1-architecture/capability-reconciliation.json

@@ -39,6 +39,7 @@
       "skills/engineering/react-doctor/SKILL.md": "skills/engineering/react-doctor/capability.json",
       "skills/engineering/simplify/SKILL.md": "skills/engineering/simplify/capability.json",
       "skills/engineering/tdd/SKILL.md": "skills/engineering/tdd/capability.json",
+      "skills/imported/benjitaylor/stageshow/SKILL.md": "skills/imported/benjitaylor/stageshow/capability.json",
       "skills/imported/david/david-agent-self-scheduling/SKILL.md": "skills/imported/david/david-agent-self-scheduling/capability.json",
       "skills/imported/david/david-anti-sleep/SKILL.md": "skills/imported/david/david-anti-sleep/capability.json",
       "skills/imported/david/david-brain-to-docs/SKILL.md": "skills/imported/david/david-brain-to-docs/capability.json",
@@ -199,6 +200,7 @@
       "skills/engineering/react-doctor/SKILL.md",
       "skills/engineering/simplify/SKILL.md",
       "skills/engineering/tdd/SKILL.md",
+      "skills/imported/benjitaylor/stageshow/SKILL.md",
       "skills/imported/david/david-agent-self-scheduling/SKILL.md",
       "skills/imported/david/david-anti-sleep/SKILL.md",
       "skills/imported/david/david-brain-to-docs/SKILL.md",
@@ -330,8 +332,8 @@
     "missing": []
   },
   "counts": {
-    "callable_skills": 158,
-    "manifests": 158,
+    "callable_skills": 159,
+    "manifests": 159,
     "package_exports": 20,
     "private_declarations": 1,
     "unclassified": 0

artifacts/validation/stageshow/2026-11-01.json

@@ -0,0 +1,134 @@
+{
+  "activation": {
+    "lifecycle": "candidate",
+    "performed": false,
+    "publish_targets": [],
+    "validation_status": "blocked"
+  },
+  "browser_launcher_sha256": "48e9ee06dc76b378bf6f3b701f72a844a2db33f5056086cd5ab2642fa394d271",
+  "browser_video_acceptance": {
+    "limitation": "film.mjs exports PNG stills/contact sheets; an actual video-recording and decode/visual inspection step is still required",
+    "required_checks": [
+      "matching official browser for locked playwright-core 1.48.2",
+      "browser sandbox active",
+      "no host mounts or private content",
+      "test network denial proven",
+      "representative still and loop",
+      "compact layout",
+      "reduced motion",
+      "truthful failed rehearsal status",
+      "caption escaping at runtime",
+      "video decodes with expected duration, dimensions, changing frames and final state",
+      "output containment",
+      "browser/server shutdown",
+      "independent visual review"
+    ],
+    "status": "not run",
+    "video_artifact": null,
+    "visual_review": "not performed"
+  },
+  "capability": "stageshow",
+  "changes": [
+    "Preserved existing candidate, notices, omitted-asset policy, lockfile and two film.mjs patches.",
+    "Enabled chromiumSandbox explicitly for both browser-selection paths; no weaker retry.",
+    "Updated source hashes and validation-status prose without changing candidate lifecycle or publication targets."
+  ],
+  "checks": [
+    {
+      "browser_launched": false,
+      "failures": 3,
+      "name": "launcher regression before fix",
+      "status": "expected failure",
+      "tests": 4
+    },
+    {
+      "browser_launched": false,
+      "command": "PATH=/opt/homebrew/opt/python@3.11/libexec/bin:$PATH /opt/homebrew/bin/python3.11 -m unittest tests.test_stageshow_intake tests.test_stageshow_browser_launcher tests.test_capability_registry tests.test_audit_capabilities tests.test_compile_runtime tests.test_install_runtime tests.test_documented_commands",
+      "failures": 0,
+      "name": "focused Stack tests",
+      "python": "3.11.15",
+      "status": "passed",
+      "tests": 59
+    },
+    {
+      "command": "node --check skills/imported/benjitaylor/stageshow/scripts/browser.mjs",
+      "name": "JavaScript syntax",
+      "status": "passed"
+    },
+    {
+      "command": "python3 scripts/build-capability-registry.py --check",
+      "name": "capability registry",
+      "status": "passed"
+    },
+    {
+      "command": "git diff --check -- skills/imported/benjitaylor/stageshow tests/test_stageshow_browser_launcher.py",
+      "name": "patch whitespace",
+      "status": "passed"
+    },
+    {
+      "name": "fresh-reader check",
+      "scope": "changed integration-contract prose and validation follow-up; one ambiguous phrase clarified",
+      "status": "passed"
+    },
+    {
+      "failures": 1,
+      "name": "initial default-Python test run",
+      "reason": "Python 3.9 lacked tomllib for an existing documented command; Python 3.11 rerun passed",
+      "status": "failed",
+      "tests": 59
+    },
+    {
+      "name": "bun skill guards",
+      "reason": "This Stack repository uses Python unittest and has no root Bun package or test:skill-guards script.",
+      "status": "not applicable"
+    },
+    {
+      "name": "Claude/Codex behavioral skill evaluation",
+      "reason": "Candidate remains inactive; changed prose records validation status and the sandbox patch. Cross-runtime video acceptance requires the blocked isolated setup.",
+      "status": "not run"
+    }
+  ],
+  "imported_file_hashes_digest": "a9c16b987382624e4d7e80eec0990376488f73da1b3808e0000d725b6f1916ef",
+  "isolation_attempt": {
+    "booted": false,
+    "browser_launched": false,
+    "cleanup": "Unbooted VM definition deleted; Lima reports no instance",
+    "container_runtime": false,
+    "download_probes": [
+      {
+        "result": "curl exit 6: could not resolve host",
+        "url": "https://cloud.debian.org/images/cloud/bookworm/latest/debian-12-genericcloud-arm64.qcow2"
+      },
+      {
+        "result": "curl exit 6: could not resolve host",
+        "url": "https://mcr.microsoft.com/v2/playwright/manifests/v1.48.2-jammy"
+      }
+    ],
+    "host_mounts": [],
+    "host_public_key_loading": false,
+    "proxy_environment_propagation": false,
+    "result": "VM creation stopped on a denied default image-cache write",
+    "ssh_agent_forwarding": false,
+    "test_listener_started": false,
+    "vm": "Lima plain-mode Debian 12 arm64"
+  },
+  "prior_validation": {
+    "browser_video": "user-reported incomplete after guest DNS failure; prior VM removed",
+    "checked_in_review": "skills/imported/benjitaylor/stageshow/STACK-REVIEW.md",
+    "install_typecheck_build": "user-reported pass; newer receipts not located; not independently rerun",
+    "prohibited_diagnostic": "not retried; no privilege elevation or bypass attempted"
+  },
+  "recorded_at": "2026-11-01T22:24:22.668125+00:00",
+  "resume_requirements": [
+    "Use a supported runner that permits setup-only official VM/browser/dependency downloads and VM image-cache writes, or supply a verified offline image/bundle.",
+    "Bind browser and dependency assets to the existing lockfile and verify their identity before executing them.",
+    "Copy only the pinned candidate and synthetic fixture into a fresh isolated environment; enforce and prove network denial before any test execution.",
+    "Keep the browser sandbox enabled and stop on isolation failure; do not reuse signed-in browsers, alter host security controls or retry the denied diagnostic.",
+    "Record and inspect a real video before changing the hold. Review catalog activation separately from runtime publication; publication is prohibited in this task."
+  ],
+  "schema_version": 1,
+  "source_state": "existing staged candidate plus uncommitted follow-up; no commit or publication performed",
+  "stack_base_commit": "0da4f2e3c8598bbb807db2a90e014366094124eb",
+  "status": "blocked-before-browser-video-validation",
+  "upstream_revision": "802057409787133703c56001080169e347305572"
+}

artifacts/validation/stageshow/2026-11-09-accepted.json

@@ -0,0 +1,98 @@
+{
+  "artifact_root": "artifacts/validation/stageshow/local-2026-11-09",
+  "artifacts_sha256": {
+    "outputs/browser-acceptance.json": "83abf1e2f03d92f7af74fb45c010440c320787ea28f7afd91ddddb64d3326ae9",
+    "outputs/caption-audit.json": "7d97a352845fc22bcf3c53b00108e159d965beacd2e1ba222a7d70ce078e040d",
+    "outputs/failure.json": "4d472b836a19c52239e078dbf26ef565705b0b697c07326dbe65babf8b7adedd",
+    "outputs/loop-probe-final.json": "3e03a910ad32941a329985ee5e77b558bfbdfc2c61076f7d69024341c69c37fb",
+    "outputs/loop-ui.mp4": "d06a9415c941242b355bcfe0cb253582cd54671153e6a96cd4a18444981cbd82",
+    "outputs/loop-video.json": "69ee8648dc6cadf67de36cff4966eb0d4935872bbdfb7874cd0dddaf4355e09f",
+    "outputs/representative-compact.json": "7230a75fd54713b135cb75ddee4c803643ea983971038b1abee92807131c7f1d",
+    "outputs/representative-loop-final.json": "4182b772d8fe7d1e627a496359d636cbf6287b52957eb912b67f2a985a3f6246",
+    "outputs/representative-still.json": "7230a75fd54713b135cb75ddee4c803643ea983971038b1abee92807131c7f1d",
+    "outputs/sample-ui.mp4": "407a130327cdce1833285fbe592c4c0ff95b2ac7e004718a756032204be8b320",
+    "outputs/video-probe-final.json": "6e85b73639860f8a240a93510aa5a147b08318ebab8cae488e57fdc8bc02088b"
+  },
+  "capability": "stageshow",
+  "checks": {
+    "build": "passed offline in VM",
+    "caption_escape": "markup label round-tripped; zero inserted tags or executed handlers",
+    "compact": "390px, 358px design, no overflow; passed gate",
+    "dependencies": "exact lockfile npm ci --ignore-scripts; Debian signed-index version pins and SHA-256 list retained",
+    "failed_rehearsal": "exit 1 preserved in process and report; no success claim",
+    "official_node_sha256": "1c4a9933a5e45bc88f54f70b5f91232c127ec49f1a5989d23fb85824c7adf9b7",
+    "output_containment": "all named exports under approved validation outputs; no source helper/lockfile mutation, output symlink or HTTP listener; arbitrary hostile --out paths are not a supported safety boundary",
+    "reduced_motion": "wide and compact posters stable; final success state",
+    "representative_loop": "complete sampling, no findings, rehearsal passed with unchanged thresholds",
+    "representative_still": "passed gate",
+    "shutdown": "no remaining browser/node/listener processes; VM stopped",
+    "typecheck": "passed offline in VM",
+    "video": {
+      "decode": "both entire streams decoded without errors",
+      "loop": {
+        "codec": "h264",
+        "decoded_frames": 200,
+        "dimensions": [
+          640,
+          360
+        ],
+        "duration_seconds": 8,
+        "fps": 25,
+        "states": "saved/reset twice"
+      },
+      "native_recording": "official Playwright VP8 encoder; native tail trimmed when producing declared-duration H.264 exports",
+      "sample": {
+        "codec": "h264",
+        "decoded_frames": 300,
+        "dimensions": [
+          640,
+          480
+        ],
+        "duration_seconds": 12,
+        "final_state": "Account created",
+        "fps": 25
+      },
+      "visual_inspection": "decoded sequence, final frame and loop contact sheets inspected by primary; fresh independent review recorded separately"
+    },
+    "visual_review": "Primary decoded-frame inspection and independent Sol High review verified both MP4s; corrected still/compact evidence reviewed separately before install."
+  },
+  "isolation": {
+    "chromium_sandbox": "verified PID namespace and additional renderer seccomp; no unsandboxed retry",
+    "content": "fully inlined synthetic local file pages; no listener",
+    "environment": "allowlisted env -i",
+    "host_mounts": [],
+    "image_digest": "sha512:52eb678130e85a9bf9f3cf4f7181e060fa60a5db45373717474c5ff9305645c5e6cab8b05ca042bcfa7921d2ca29cf9fd2e815f75abe2d168557ad7207af127b",
+    "network_probes": {
+      "external_browser_navigation": "denied",
+      "ipv4": "EPERM",
+      "ipv6": "EPERM"
+    },
+    "private_credentials": false,
+    "privilege_elevation_used": false,
+    "signed_in_state": false,
+    "test_network": "inherited seccomp denies all non-UNIX/non-netlink sockets and io_uring_setup; NNP; no inherited sockets",
+    "vm": "Lima 2.2.0 VZ Debian 12 arm64"
+  },
+  "limitations": [
+    "Representative routes only; full retained example catalog not certified.",
+    "Exploratory form/loading helper scans reported sampling gaps and/or compact framing findings; preserved as failed/inconclusive.",
+    "film.mjs exports PNGs; encoded video remains a separate recording/decode step.",
+    "Host-side preparatory typecheck/build ran before VM acceptance; authoritative typecheck/build were repeated under the VM offline rule."
+  ],
+  "recorded_date": "2026-11-09",
+  "schema_version": 1,
+  "scope": "representative synthetic browser/video validation; local runtime installation separately receipted",
+  "source": {
+    "browser_revision": "1140",
+    "browser_version": "130.0.6723.31",
+    "helper_sha256": {
+      "package-lock.json": "092ee4aa51f4f38df3c5ba35708ef288a533a6c9b7078fcb5b71897d6ac5e731",
+      "scripts/browser.mjs": "48e9ee06dc76b378bf6f3b701f72a844a2db33f5056086cd5ab2642fa394d271",
+      "scripts/film.mjs": "354200847958a4573eeb0da9ba4e061fc4f2ec1eecebf3df9b91f05e747f08a3"
+    },
+    "playwright_core": "1.48.2",
+    "upstream_revision": "802057409787133703c56001080169e347305572"
+  },
+  "status": "passed",
+  "thread_id": "01a1c1bb-c674-7013-a1ee-dcaf8ede8354"
+}

artifacts/validation/stageshow/2026-11-09.json

@@ -0,0 +1,53 @@
+{
+  "activation_performed": false,
+  "authorization": "User requested local availability in Claude and Codex. Isolated validation and local installation are authorized; no additional confirmation of those actions is required.",
+  "browser_video_test": "not run",
+  "capability": "stageshow",
+  "observed_blockers": [
+    {
+      "check": "dependency setup",
+      "result": "curl exit 6: registry.npmjs.org could not be resolved"
+    },
+    {
+      "check": "offline validation assets",
+      "result": "No cached matching browser or Lima VM image; package node_modules absent"
+    },
+    {
+      "check": "normal runtime compiler",
+      "result": "refusing to stage a dirty source tree"
+    },
+    {
+      "check": "runtime stage write probe",
+      "result": "Operation not permitted"
+    },
+    {
+      "check": "Claude runtime parent write probe",
+      "result": "Operation not permitted"
+    },
+    {
+      "check": "Codex runtime parent write probe",
+      "result": "Operation not permitted"
+    },
+    {
+      "check": "runtime receipt write probe",
+      "result": "Operation not permitted"
+    }
+  ],
+  "preserved": {
+    "browser_sandbox_required": true,
+    "candidate_lifecycle": true,
+    "isolated_video_acceptance_required": true,
+    "prior_changes": true,
+    "prior_receipt": "artifacts/validation/stageshow/2026-11-01.json"
+  },
+  "recorded_at": "2026-11-09T19:09:17.331164+00:00",
+  "resume": [
+    "Run setup with access to official dependency and browser-image hosts, or supply verified offline assets.",
+    "Validate a real synthetic UI video in isolation with the browser sandbox enabled and test network access denied.",
+    "Prepare a clean isolated source commit containing only the reviewed integration changes; preserve the dirty working checkout.",
+    "Use the normal compiler and atomic installer with permitted runtime staging, Claude/Codex target and receipt writes."
+  ],
+  "runtime_installation_performed": false,
+  "schema_version": 1,
+  "status": "blocked-by-execution-environment"
+}

artifacts/validation/stageshow/local-2026-11-09/audit-hooks.mjs

@@ -0,0 +1,21 @@
+// Validation-only observer: actual film source/launcher stay byte-for-byte intact.
+import {chromium} from 'playwright-core';
+import fs from 'node:fs';
+import assert from 'node:assert/strict';
+const original=chromium.launch.bind(chromium);
+chromium.launch=async options=>{
+ assert.equal(options.chromiumSandbox,true);
+ const browser=await original(options);const newPage=browser.newPage.bind(browser);
+ browser.newPage=async options=>{
+  const page=await newPage(options);const setContent=page.setContent.bind(page);
+  page.setContent=async html=>{
+   const result=await setContent(html);
+   const payloads=await page.locator('figcaption').allTextContents();
+   const injected=await page.locator('figcaption img, figcaption script').count();
+   const executed=await page.evaluate(()=>window.__captionExecuted||0);
+   assert.equal(injected,0);assert.equal(executed,0);
+   if(process.env.CAPTION_AUDIT)fs.writeFileSync(process.env.CAPTION_AUDIT,JSON.stringify({payloads,injected,executed,escaped:html.includes('<img')},null,2));
+   return result;
+  };return page;
+ };return browser;
+};