feat(hub): integrate the real code graph

[theDakshJaitly]

Summary

• merge Lane A as an explicit dependency of the Activity-based Hub stack
• add an internal repository GraphPort adapter with exact freshness-bound Search, source, relations, impact, and code-reference reads
• expose real grouped graph Search, structured graph Health, and the read-only Code workspace
• run refresh and rebuild only as explicit persistent Hub jobs, with Wiki still honestly unavailable
• preserve engine ranking, graph protocol output, Activity, TUI behavior, and package-root declarations

Stack

• base: feat/hub-activity-timeline
• dependency merge: feat/graph-freshness-recovery
• draft only; this PR does not target or merge into main

Verification

• root typecheck
• 882 root tests with bounded local workers
• 75 Hub web unit tests
• 38 graph evaluator and 47 comparison evaluator tests
• production build and private declaration leak check
• 20 Playwright/axe tests at 1024 and 1440, reduced motion, zero outbound requests, and Darwin visual baselines
• real-process Graph Search/Code/Health and stale-read abstention
• packed npm install, bootstrap, real graph reads, explicit refresh, corrupt-index rebuild, source nonmutation, and clean shutdown
• git diff --check

The first Ubuntu browser run is expected to supply the new platform-specific Code baseline; that artifact will be committed before this draft is marked ready.

Deferred

• real Wiki search, health, and maintenance pending the completed teammate Wiki engine and Lane D conformance
• Catch Up, activity creation, Inbox, Relays, Workstreams, deep links, graph visualization, and frontend redesign