docs: update project documentation for v1.66.1.0

CLAUDE.md: add gstack-wtree/gstack-evidence/gstack-issue-guard to the bin/
structure line and tracker-guard.ts to the lib/ line. README.md +
docs/skills.md: /careful descriptions no longer claim every warning is
overridable — the HIGH tier hard-denies root/home recursive deletes and
default-branch force-pushes; skills.md also documents the additive-only
careful-patterns.txt warn rules.

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

CLAUDE.md

@@ -153,7 +153,7 @@ gstack/
 ├── investigate/     # /investigate skill (systematic root-cause debugging)
 ├── spec/            # /spec skill (five-phase spec → GitHub issue, optional agent spawn, /ship auto-closes)
 ├── retro/           # Retrospective skill (includes /retro global cross-project mode)
-├── bin/             # CLI utilities (gstack-repo-mode, gstack-slug, gstack-config, etc.)
+├── bin/             # CLI utilities (gstack-repo-mode, gstack-slug, gstack-config, gstack-wtree, gstack-evidence, gstack-issue-guard, etc.)
 ├── document-release/ # /document-release skill (post-ship doc updates + Diataxis coverage map)
 ├── document-generate/ # /document-generate skill (Diataxis doc generator: tutorial/how-to/reference/explanation)
 ├── cso/             # /cso skill (OWASP Top 10 + STRIDE security audit)
@@ -166,7 +166,7 @@ gstack/
 │   ├── test/        # Integration tests
 │   └── dist/        # Compiled binary
 ├── extension/       # Chrome extension (side panel + activity feed + CSS inspector)
-├── lib/             # Shared libraries (worktree.ts, egress-receipt.ts, context-bill.ts, redact-engine.ts, code-intelligence/)
+├── lib/             # Shared libraries (worktree.ts, egress-receipt.ts, context-bill.ts, redact-engine.ts, tracker-guard.ts, code-intelligence/)
 ├── docs/designs/    # Design documents
 ├── setup-deploy/    # /setup-deploy skill (one-time deploy config)
 ├── .github/         # CI workflows + Docker image

README.md

@@ -223,7 +223,7 @@ Each skill feeds into the next. `/office-hours` writes a design doc that `/plan-
 | Skill | What it does |
 |-------|-------------|
 | `/codex` | **Second Opinion** — independent code review from OpenAI Codex CLI. Three modes: review (pass/fail gate), adversarial challenge, and open consultation. Cross-model analysis when both `/review` and `/codex` have run. |
-| `/careful` | **Safety Guardrails** — warns before destructive commands (rm -rf, DROP TABLE, force-push). Say "be careful" to activate. Override any warning. |
+| `/careful` | **Safety Guardrails** — warns before destructive commands (rm -rf, DROP TABLE, force-push). Say "be careful" to activate. Override any MEDIUM warning; root/home recursive deletes and default-branch force-pushes are hard-denied. |
 | `/freeze` | **Edit Lock** — restrict file edits to one directory. Prevents accidental changes outside scope while debugging. |
 | `/guard` | **Full Safety** — `/careful` + `/freeze` in one command. Maximum safety for prod work. |
 | `/unfreeze` | **Unlock** — remove the `/freeze` boundary. |

docs/skills.md

@@ -48,7 +48,7 @@ Detailed guides for every gstack skill — philosophy, workflow, and examples.
 | [`/sync-gbrain`](#sync-gbrain) | **Keep Brain Current** | Refresh gbrain against this repo's code; teach the agent when to use `gbrain search`/`code-def` over Grep. Idempotent; safe to re-run. |
 | | | |
 | **Safety & Utility** | | |
-| [`/careful`](#safety--guardrails) | **Safety Guardrails** | Warns before destructive commands (rm -rf, DROP TABLE, force-push, git reset --hard). Override any warning. Common build cleanups whitelisted. |
+| [`/careful`](#safety--guardrails) | **Safety Guardrails** | Warns before destructive commands (rm -rf, DROP TABLE, force-push, git reset --hard). Override any MEDIUM warning; root/home recursive deletes and default-branch force-pushes are hard-denied. Common build cleanups whitelisted. |
 | [`/freeze`](#safety--guardrails) | **Edit Lock** | Restrict all file edits to a single directory. Blocks Edit and Write outside the boundary. Accident prevention for debugging. |
 | [`/guard`](#safety--guardrails) | **Full Safety** | Combines /careful + /freeze in one command. Maximum safety for prod work. |
 | [`/unfreeze`](#safety--guardrails) | **Unlock** | Remove the /freeze boundary, allowing edits everywhere again. |
@@ -1076,7 +1076,7 @@ Say "be careful" or run `/careful` when you're working near production, running
 
 Common build artifact cleanups (`rm -rf node_modules`, `dist`, `.next`, `__pycache__`, `build`, `coverage`) are whitelisted — no false alarms on routine operations.
 
-You can override any warning. The guardrails are accident prevention, not access control.
+You can override any MEDIUM warning. Two catastrophic shapes are hard-denied instead of asked: recursive deletes of exactly `/`, `~`, or `$HOME`, and force-pushes to the repo's default branch (`--force-with-lease` never triggers the deny; the escape hatch is ending the session-scoped `/careful` session). You can also add your own warn rules — one POSIX ERE per line — in `~/.gstack/careful-patterns.txt` (global) or `~/.gstack/projects/<slug>/careful-patterns.txt` (per-project); custom patterns only ever add warnings, never suppress the built-ins. The guardrails are accident prevention, not access control.
 
 ### `/freeze`