Add a gated Known Limitations and Deferred Work section to every package README

Every packages/*/* README now carries a canonical '## Known Limitations and
Deferred Work' section: condensed, evidence-backed bullets for consumer-visible
gaps (unimplemented features, platform caveats, MVP cuts) and consciously
postponed work (TODO/FIXME/XXX markers, RFC deferrals still open). The ten
pre-existing ad-hoc variants ('What is NOT here (TODO)', 'Deferred',
'Limitations (MVP)', 'Known limitations (tracked TODOs)', ...) are normalized
into the canonical heading.

A new doc-sync gate, scripts/verify-readme-limitations.ts, enforces the shape:
exactly one limitations-like heading per package README, byte-equal to the
canonical h2, with at least one bullet; near-miss headings fail so variants
cannot creep back. Packages with genuinely nothing to declare (dsh-brand,
dsh-timeout, dsh-subagent-mock, dsh-app-boot) are whitelisted in the script and
must NOT carry the section; whitelist entries are validated against the scanned
package set so a rename fails loud.

Wired into the doc-sync chain (package.json) and the run-gates doc-sync leaf
set; the standing rule lands in packages/AGENTS.md and the adding-a-package
cookbook; decision record in
docs/rfc/implemented/process/2026-07-10-readme-known-limitations-gate.md
(RFC index regenerated).

Also fixes two stale '(deferred)' markers claiming dsh-compact-basic is
unimplemented (the dsh-compact seam README's package table and the seam's
module doc comment).

packages/hooks/hooks-claude/README.md

@@ -50,8 +50,11 @@ The matcher subject is the tool name (`PreToolUse`/`PostToolUse`), the session s
 
 Injected context carries an explicit `{ kind: 'plugin', plugin: 'hooks-claude' }` source. `agent.inject()` defaults a missing source to `{ kind: 'user' }`, which would mislabel plugin context as a user prompt — so the bridge always names itself.
 
-## Deferred (faithful-but-degraded)
+## Known Limitations and Deferred Work
 
 - **`updatedInput` (tool-input rewrite)** is logged + warned, **not honored** — input rewrite is a deferred consistency-design problem ([the pre-tool-input-rewrite RFC](../../../docs/rfc/proposed/feature/2026-06-30-pre-tool-input-rewrite.md)).
 - **`systemMessage`** (a hook's user-facing warning) is logged + warned, **not surfaced** — there is no user-message channel on these seams yet (only model-facing `additionalContext`). The shared merge collects it; the bridge does not yet render it.
 - **Stop loop-guard.** CC breaks an infinite force-continue with `stop_hook_active` (true once a Stop hook has fired this run) plus a max-consecutive cap; both are deferred (`TODO(stop-loop-guard)`). Today `stop_hook_active` is always `false`, so a Stop hook that unconditionally blocks would force-continue every step — a hook author must self-limit until the guard lands.
+- **`{"continue": false}` is recorded, not enforced** — the merge computes the `stop`/`stopReason` outcome and the `hook/result` event records decision `stop`, but the run is not halted (`TODO(hook-continue-false)`).
+- **`SessionStart` cannot gate the first turn** — `agent/session-start` is a synchronous emit, so a hook's injected context lands best-effort before turn 1 (`TODO(session-start-gating)`).
+- **Hook config is process-level** — one `configPath` parsed at load for the whole process; per-session discovery of a project-local config is deferred (`TODO(per-session-hook-config)`).