chore(memory): BDR-031 + BLK-009 + LRN-043 + LRN-044

- BDR-031: global CLAUDE.md lightening = compression, not path-scope /
  externalization (path-scoped user rules broken, #21858). 317 -> 275.
- BLK-009: user-level path-scoped rules don't load (#21858, 2.1.190),
  proven by 3-file probe. Upstream/open.
- LRN-043: routing compression — cut name-obvious lines, keep
  non-derivable signal (misleading names, gstack fallbacks) + catch-all.
- LRN-044: Edit/Write refuse to write through a symlink — resolve to
  the real path (readlink -f) first.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W9sqAwZxBMZSynZoVrEJhd

.claude/memory/blockers.md

@@ -106,3 +106,14 @@ rules:
 - **2026-06-23 UPDATE — Solution REVERTED, status downgraded to UPSTREAM/open** (commit b9c3937): the `PLAYWRIGHT_HOST_PLATFORM_OVERRIDE` solution above does NOT work on 26.04. The fallback build downloads to 100% then HANGS at extraction (chrome binary never appears, no headless-shell download starts; reproduced on real machine + sandbox) → turned a 0.5s fast-fail into an install-blocking hang (user Ctrl+C). Reverted to the fast-fail (non-fatal; gstack OFF by default, browser only for /browse,/qa,screenshots). The earlier "verified ldd + headless render" was an isolated test on a sibling already-extracted build (rev 1228) — it masked the rev-1208 install-path hang. **Real fix = upstream**: gstack bumps Playwright to a version that lists ubuntu26.04. Until then gstack's browser is unavailable on 26.04, install completes cleanly. See [[LRN-038]] correction.
 
 - **2026-06-23 FINAL — RESOLVED** (commit 3b8ffb1): gstack browser now works on Ubuntu 26.04. Two layers fixed: (1) bumped gstack's pinned Playwright 1.58.2 → 1.61 (`bun add playwright@latest` in the submodule; 1.61 ships a native ubuntu26.04 build — chromium rev 1228), automated in the installer (`gstack_bump_playwright_if_unsupported`, idempotent, OS-gated); (2) `GSTACK_CHROMIUM_NO_SANDBOX=1` to work around the AppArmor userns restriction (`sysctl kernel.apparmor_restrict_unprivileged_userns=1`), persisted to `.bashrc` + installer Step 9 (sysctl-gated). Verified end-to-end: `browse goto https://example.com` → "Navigated (200)". Caveat: the Playwright bump is a local submodule edit, reset by `git submodule update`, re-applied by the next install. See [[BDR-029]], [[LRN-040]].
+
+---
+
+## BLK-009 — user-level path-scoped rules don't load (#21858) — still broken in CC 2.1.190
+
+- **Date**: 2026-06-25
+- **Friction**: tried to scope a global rule to matching files via `paths:` frontmatter in `~/.claude/rules/<name>.md` — the rule never injects, even when a matching file (`*.probe`) is read in a fresh session. Blocks any "load this guidance only for matching files" strategy at the user level.
+- **Real cause**: GitHub issue #21858 — user-level (`~/.claude/rules/`) rules carrying `paths:` frontmatter are not evaluated/injected; still unfixed in 2.1.190. (Project-level path-scoped rules not tested here.)
+- **Probe method**: 3-file probe — `_probe.md` (`paths: ["**/*.probe"]`, sentinel `SENTINEL_USER_RULE_LOADED`), `_probe_ctl.md` (NO `paths`, control sentinel `CONTROL_NOPATHS_LOADED`), `_probe_target.probe` (target, read in a fresh session). Result: control sentinel PRESENT in session context, path-scoped sentinel ABSENT → the path-scoped rule did not load. Probe files removed after.
+- **Status**: upstream, open. Workaround: don't rely on user-level path-scoping → keep global guidance unconditional + COMPRESSED ([[BDR-031]]). Side-note: native auto-memory = "on" but writes nothing yet (fresh machine). Re-test on CC upgrades.
+- **Reference**: GitHub #21858. Linked to [[BDR-031]], [[LRN-044]].