docs: sync every doc surface with the v1.63 release

/document-release audit (4-lane, all claims verified against branch code):

- README: gstack-egress + gstack-context-bill rows in the standalone-binaries
  table; Privacy & Telemetry gains the receipted-egress bullet (attempted-
  egress framing per the shipped threat model).
- ARCHITECTURE: /health is liveness-only, POST /extension-token endpoint row
  + bootstrap mechanics paragraph; new Egress receipt ledger subsection under
  Security model; eval persistence covers the sharded runner, GSTACK_EVAL_DIR,
  and the finalized-run baseline rule.
- CLAUDE.md: sharded test scripts in Commands; sharded semantics in the
  detached-evals section; PTY skill seeding in the hermetic section; egress
  invariant block beside the other server-egress invariants; catalog-budget
  ceiling beside the 160KB token ceiling; project-tree entries for
  lib/egress-receipt.ts, lib/context-bill.ts, scripts/test-paid-shards.ts.
- CONTRIBUTING: seedSkills + live-tree seeding in the hermetic paragraph;
  sharded runner in detached runs; catalog-budget in the Tier 1 list.
- BROWSER: extension token bootstrap section, tunnel egress receipts section,
  identity-pin migration note in manual install.
- REMOTE_BROWSER_ACCESS: tunnel-start receipt bullet in the security model.
- gbrain docs: /sync-gbrain + brain-sync egress-receipt behavior documented;
  dead consumer-token instructions removed (consumer machinery deleted this
  release); new fail-closed refusal added to the error catalog.
- CHANGELOG: measured-vs-ceiling catalog numbers, contributor notes for the
  external-service tier move and the PTY single-line AskUserQuestion parser,
  release date.
- TODOS: /health token-distribution TODO resolved by this release, removed;
  port-wave follow-up sections re-labeled to the shipped version.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/gbrain-sync.md

@@ -18,7 +18,7 @@ GBrain.
 By design, these stay local even when sync is on:
 
 - Credentials: `.auth.json`, `auth-token.json`, `sidebar-sessions/`,
-  `security/device-salt`, consumer tokens in `config.yaml`
+  `security/device-salt`
 - Machine-specific state: Chromium profiles, ONNX model weights,
   caches, eval-cache, CDP-profile, one-time prompt markers
   (`.welcome-seen`, `.telemetry-prompted`, `.vendoring-warned-*`, etc.)
@@ -80,9 +80,7 @@ On machine B:
    ```
 3. Run `gstack-brain-restore`. That clones the repo, rehydrates your
    learnings/plans/retros, and re-registers the git merge drivers.
-4. Re-enter consumer tokens (they're machine-local and NOT synced —
-   `gstack-config set gbrain_token <your-token>`).
-5. Next skill: your yesterday-on-machine-A learning surfaces. That's the
+4. Next skill: your yesterday-on-machine-A learning surfaces. That's the
    magical moment.
 
 ## Status, health, and queue depth
@@ -141,6 +139,12 @@ To remediate:
 There's a defense-in-depth hook at `~/.gstack/.git/hooks/pre-commit` that
 runs the same scan if you manually `git commit` against the repo.
 
+Separately (v1.63.0.0+), every push writes a tamper-evident receipt to the
+egress ledger (`~/.gstack/security/egress.jsonl`) *before* anything is
+sent, fail-closed: if the receipt can't be written, the push is refused
+and the queue is preserved. Inspect the ledger with `gstack-egress list`
+and verify its hash chain with `gstack-egress verify`.
+
 ## Two-machine conflicts
 
 If you write on machine A and machine B the same day, both will push