chore(smoke): run smoke:tui for real in GitHub CI

[cliffhall]

Closes #2408

What changed

smoke:tui self-skipped whenever process.env.CI was set, so CI gave no signal on TUI regressions. This PR removes that skip, so the smoke now runs in the build job's existing npm run smoke step. The workflow's steps are unchanged; only its comments move.

Why removing the skip alone was not enough

The PTY wrapper from #2147 had already removed the original blocker, a headless runner with no TTY, and ubuntu-latest ships util-linux script(1). But with the skip removed, the smoke failed on Linux under CI=true:

• The TUI entered the alt screen (\e[?1049h) and never painted "MCP Servers", even with a 40s budget.
• The cause was Ink, not the pty. Ink reads is-in-ci, and when CI or CONTINUOUS_INTEGRATION is set to anything but 0/false it suppresses every interactive frame and writes only the last one on unmount.
• Bisected in ubuntu:24.04 (util-linux 2.39.3) with the same spawn: CI=true gave 0 marker hits and CI=false gave 1. The pty's 0×0 window size was ruled out: it renders fine unsized.

So the smoke now pins CI: "false" and CONTINUOUS_INTEGRATION: "false" in the child's env. It uses "false" rather than deleting the keys because is-in-ci treats exactly that value as not-CI, whatever else the runner exports.

Verification

• Linux, same util-linux as ubuntu-latest: in ubuntu:24.04 with CI=true CONTINUOUS_INTEGRATION=true, 3/3 runs smoke:tui OK — rendered "MCP Servers" at ~270ms and was still running 2000ms later. The survival and raw-mode-error assertions from smoke:tui reports success for a TUI that crashed: it asserts first paint, not survival #2147 still apply.
• macOS: npm run local:gate passed (EXIT=0), including smoke:tui OK.
• The first real proof on a GitHub runner is this PR's own build job.

Docs

Everything that described smoke:tui as local-only or self-skipping is updated: docs/quality-gate.md (the canonical CI-vs-local split), the pre-push-gate skill, AGENTS.md, README.md, clients/launcher/README.md, and the workflow-gate header and test name. The local gate now has one local-only step (Firefox) where it had two.

The publish job's comment is also corrected: it claimed smoke:tui self-skipped inside pack:verify, but pack:verify only runs --tui --help.

No screenshots: this changes CI and smoke tooling, not the TUI itself.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🔵 Needs a closer look

Add regression coverage proving both CI variables are forced to "false" in the spawned child.

Review effort: Balanced
Findings: None

What changed in this PR

Enables the PTY-backed TUI smoke test in GitHub CI by preventing Ink from suppressing interactive rendering.

Changes:

• Removes the CI self-skip and overrides child CI variables.
• Updates workflow-gate tests, comments, and documentation.
• Corrects CI and publish workflow guidance.

File	Description
scripts/​smoke-tui.mjs	Enables CI execution; the environment override lacks regression coverage.
scripts/​lib/​workflow-gate.test.mjs	Updates the TUI smoke test description.
scripts/​lib/​workflow-gate.mjs	Documents the revised CI/local split.
README.md	Updates the local-gate summary.
docs/​quality-gate.md	Documents TUI smoke coverage in CI.
clients/​launcher/​README.md	Documents CI execution and environment handling.
AGENTS.md	Updates mandatory gate guidance.
.github/​workflows/​main.yml	Corrects smoke and publishing comments.
.claude/​skills/​pre-push-gate/​SKILL.md	Updates gate procedure guidance.

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[cliffhall]

Copilot review round 1 — closed. Findings: none, no inline comments, no suppressed block.

The headline suggestion (regression coverage proving CI/CONTINUOUS_INTEGRATION are forced to "false" in the child) is declined: this PR's own CI is that coverage. ubuntu-latest exports CI=true, so if either pin were dropped, Ink would suppress its interactive frames, the TUI would never paint the "MCP Servers" marker, and smoke:tui would fail in the build job. I reproduced exactly that in ubuntu:24.04 before adding the pin. A unit test would mean moving the env construction into a separate tested module just to assert a literal the smoke already exercises end to end.

Loop stopped per the round-exit rule: the only item was declined, so another round would only re-argue it.