Architecture docs hygiene for permission queue + events (CL-5668, CL-5669)

[TheGreatAxios]

Summary

• Keep docs/ARCHITECTURE.md permission section truthful after CL-5662 / CL-5663 / CL-5664 fixed or superseded: document headless grant reconciliation (src/permission/queue.ts), worktree-aware project grants, and point the wall-clock budget paragraph at gate-wire + permission queue instead of deleted use-gates.
• Drop the stale Ink-era use-gates / pendingPlan plan-approval sentence from docs/IMPLEMENTATION.md.
• CL-5669 Events table hygiene already on main (Partial heading + PRODUCTION_REACTOR_TYPES as canonical); no further Events change needed.

Why not a known-gaps callout

CL-5668 originally asked for a temporary pointer to CL-5662/5663/5664. Those are Done (5662, 5664) or Canceled/superseded (5663 → CL-4995). House policy: no permanent known-issue debt for closed tickets — describe the fixed behavior instead.

Test plan

• Diff is docs-only (docs/ARCHITECTURE.md, docs/IMPLEMENTATION.md)
• Grep docs for use-gates / pendingPlan / permanent known-gap callouts — none remain in these files
• Events section still points at PRODUCTION_REACTOR_TYPES in src/tui/stream-event-map.ts
• Human skim of Permission System + Reactor Events sections for accuracy

Closes CL-5668
Closes CL-5669

[linear-code]

CL-5668

CL-5669