chore(memory): BDR-028 + LRN-039 (installer config drift guard + de-vendor)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UyNYwD4UccVw9ZCFZyJX55

.claude/memory/decisions.md

@@ -462,3 +462,15 @@ rules:
 - **Why**: a 1-function fallback fixes the actual blocker. Folding 9 prereqs into a 245-line lib was scope-creep for "npm missing"; user reverted it. Inline blocks stay readable + co-located with their step.
 - **Alternatives rejected**: centralized `lib/install-prereqs.sh` (commit 1ddeed1 — over-engineered for the real blocker, reverted); leave `npm` as a hard `err` (the original bug — aborts before the CLI install).
 - **Reference**: `install.sh` `install_node_via_nvm`, `install-plugins.sh` Step 1 jq, `doctor.sh`, commits b6cc8b1 / 2194b11. Linked to [[BLK-008]] (the chromium half of the same fresh-Ubuntu-26.04 session).
+
+---
+
+## BDR-028 — Hand-curated config is install-immutable (auto-revert guard) + de-vendor installer-managed skills
+
+- **Date**: 2026-06-23
+- **Status**: accepted
+- **Decision**: `install-plugins.sh` snapshots `CLAUDE.md` + `settings.json` + `.claude/settings.json` at start, restores them on EXIT (trap) → installer never mutates hand-curated config. `frontend-design` un-tracked (`git rm --cached` + gitignore `skills-external/frontend-design/`) — re-synced from the example-skills plugin cache every run, so vendoring = pure churn. npx-skills pollution (`/.agents/`, `/skills-lock.json`) gitignored, anchored so our `agents/` stays tracked.
+- **Why**: a fresh `make install` drifted all 4: graphify clobbered `CLAUDE.md` (deleted the `# This repo only` header) + injected aggressive MANDATORY pre-tool hooks; `claude plugin install` flipped `example-skills`→true + added `plugin-dev`; frontend-design diffed on every upstream update; darwin-skill polluted repo `.agents/` at project scope. Guard = these files maintained by hand+commit only; gitignore = generated artifacts never tracked.
+- **Caveat**: guard makes the 3 config files install-immutable — anything the installer SHOULD add must be committed by hand. Safe today: committed `settings.json` already carries the rtk hook (install skips init). `update-all.sh` needs no guard (only `claude plugin update`, no enable flips, no graphify reconfig).
+- **Alternatives rejected**: `git checkout` post-install (nukes legit uncommitted edits, depends on git state); surgical JSON/markdown patching (fragile); accept graphify's generic CLAUDE.md (loses curation).
+- **Reference**: `install-plugins.sh` guard block + `restore_curated_configs` trap, `.gitignore`, commits 51afe9b / 7de8761. Linked to [[LRN-039]].

.claude/memory/journal.md

@@ -177,3 +177,6 @@ rules:
 
 - Reverted commit 1ddeed1 (centralized `lib/install-prereqs.sh`) — over-engineered for the real blocker. Replaced with minimal npm-via-nvm fallback in `install.sh` (b6cc8b1). Re-added `jq` prereq inline + `doctor.sh` fail-level (2194b11). BDR-027.
 - Diagnosed gstack chromium fail on Ubuntu 26.04: Playwright 1.58.2 doesn't list 26.04. Fix = gated `PLAYWRIGHT_HOST_PLATFORM_OVERRIDE=ubuntu24.04-x64`, wrapper-only (no submodule edit), install + runtime (211c7d4). Verified ldd + headless render on 26.04. BLK-008, LRN-038.
+
+- Fresh-install audit: `make install` drifted 4 repo files. Root-caused each: graphify installer clobbers `CLAUDE.md` (deletes `# This repo only` header) + injects MANDATORY hooks in `.claude/settings.json`; `claude plugin install` flips `example-skills`→true + adds `plugin-dev` in `settings.json`; example-skills `cp` churns `frontend-design`; `npx skills add` pollutes repo `.agents/` + `skills-lock.json`.
+- Fix: reverted current drift (`git checkout` 3 configs); added snapshot+trap-restore guard in `install-plugins.sh` (curated config now install-immutable); de-vendored frontend-design + gitignored `/.agents/` + `/skills-lock.json` (anchored so `agents/` stays tracked). Guard tested drift→restore. Commits 51afe9b / 7de8761. BDR-028, LRN-039.

.claude/memory/learnings.md

@@ -529,3 +529,13 @@ rules:
 - **Pattern**: `PLAYWRIGHT_HOST_PLATFORM_OVERRIDE=ubuntuXX.04-<arch>` forces a fallback build. MUST include arch (`x64`/`arm64`) — bare `ubuntu24.04` fails ("does not support … ubuntu24.04"). Set it from the WRAPPER: `export` before the submodule's setup (install-time download) AND persist to the shell profile (runtime launch) — both paths call `getHostPlatform`. No submodule edit. Gate on real OS version (`sort -V` compare) so supported distros are untouched. Test with the LOCAL `./node_modules/.bin/playwright` — `bunx playwright` pulls the LATEST playwright (different browser revision than the local import), which masks the result.
 - **Future application**: any pinned tool that hardcodes an OS allowlist breaks on a fresh OS upgrade. Look for a host-platform override env before bumping/forking the dep. Prove the fallback binary actually runs (`ldd` = no missing libs + a real headless render), not just that the download resolves.
 - **Reference**: `install-plugins.sh` `playwright_platform_override()`, commit 211c7d4. Linked to [[BLK-008]].
+
+---
+
+## LRN-039 — Installers drift hand-curated config → snapshot+trap-restore guard; anchor gitignore for pollution
+
+- **Date**: 2026-06-23
+- **Context**: fresh Ubuntu `make install`. 3rd-party installers mutated repo files: graphify rewrote `CLAUDE.md`+hooks (every `graphify install`, Step 7), `claude plugin install` flipped `enabledPlugins`, the example-skills `cp` churned `frontend-design`, `npx skills add` wrote project-scope `.agents/` + `skills-lock.json`.
+- **Pattern**: file an installer rewrites but YOU curate → snapshot to a `mktemp -d` at start + `trap restore EXIT` (`cmp -s` before `cp`, revert only real diffs). Preserves pre-existing edits, no git dependency, idempotent, survives early-exit. Pure generated pollution → gitignore. ANCHOR the ignore (`/.agents/`, NOT `.agents/` and NOT `agents`) so it can't catch a legit sibling — our agents live in `agents/` (no dot). Verify with `git check-ignore -v <legit-dir>` that the pattern doesn't over-match.
+- **Future application**: audit a fresh install = `git status` right after `make install`; classify every drift as (a) curated → guard, or (b) pollution → anchored gitignore. Never `git checkout` to clean drift (destroys uncommitted work). Prove the guard with an isolated drift→restore test before trusting it.
+- **Reference**: `install-plugins.sh` `restore_curated_configs` + EXIT trap, `.gitignore` `/.agents/`, commits 51afe9b / 7de8761. Linked to [[BDR-028]].