feat(hub): deliver human-first team memory workflows

[theDakshJaitly]

What

• Rebuilds the Hub sidebar and the Overview, Inbox, Relays, Activity, and Team workbenches around human review, handoff, identity, and project-context tasks.
• Makes new Relays standalone schema-v3 records with immutable publication Git context while preserving byte-exact v1/v2 reads, recovery, and exact signed preview/apply behavior.
• Adds trustworthy Activity workflow/custom provenance and bounded human labels without rewriting schema-v1 history.
• Splits the globally mounted Home shell from a bounded Overview aggregate, with isolated source failures, honest Health/Job projections, deterministic fixtures, accessibility coverage, and calibrated release assertions.

Why

This completes the Human Team Memory integration checkpoint with human-first UX while preserving MEX's local-first Git truth, bounded reads, exact envelopes, and fail-closed mutation safety.

Type of change

• Bug fix
• New feature
• Refactor
• Docs
• CI/Tooling

How to test

1. npm run typecheck
2. npm test
3. npm test --workspace @mex/hub-web -- --run
4. npm run build
5. npx playwright test test/hub-e2e/hub.spec.ts --workers=1
6. npm run test:hub:package
7. node scripts/release-benchmark/run.mjs --assets-only --output /tmp/mex-hub-ux-assets.json

Verified locally:

• Root suite: 2,864/2,868 passed in the sandbox; the four loopback-listener cases were blocked by listen EPERM, then both affected files passed 6/6 with loopback access.
• Hub web: 388/388.
• Hub Playwright: 85/85.
• Packed Hub smoke: passed.
• Production build and asset budgets: passed with zero violations.

Checklist

• Tests pass (npm test; loopback-only cases rerun with the required local-listener permission)
• No published breaking changes; existing Relay v1/v2 and Activity v1 records remain byte-preserving and read without migration
• Tested locally with real repository and two-clone contract coverage

Safety and compatibility

• Applies the exact signed preview envelope returned by the service.
• Keeps canonical changes in the Git working tree; MEX does not commit, push, pull, notify, or perform outbound delivery.
• Keeps local drafts, identity overrides, and indexes checkout-local.
• Adds no polling, background reconciliation, or read-side writes.

Deliberately deferred

• Canonical Activity remains capped at 2,048 events / 32 MiB. Capacity exhaustion can block canonical operations that must append Activity, and Activity reads still scan and reparse the bounded corpus. Retention/indexing needs a separate pre-release design.
• Member deactivation remains available through the backend and CLI but is intentionally absent from the default Hub UI pending reversible lifecycle and Relay-stranding policy.
• Exact redesigned visual goldens are reviewed on Darwin. Ubuntu retains semantic, keyboard, overflow, and axe coverage; pinned Ubuntu 24.04 goldens remain a separate capture/review follow-up.

Code-graph changes

• This PR targets main
• A linked issue agrees on the bounded extractor/resolver scope
• The change follows the frozen LanguageExtractor or FrameworkResolver interface
• A focused fixture and assertions for the expected node/edge shape are included
• Any new grammar WASM, extension mapping, extractor, or resolver is registered
• No graph identity, reconciliation, schema, or drift-semantics changes are included, or a core / discuss-first issue is linked above

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