feat(reflexes): port 5 passive rules from fs-cortex + idempotent merger

[NestorPVsf]

Summary

Ports 5 non-duplicate passive rules (reflexes) from fermontero/fs-cortex (MIT) into the Sinapsis passive-rules tier. Adds an idempotent merger so fresh installs and upgrades both receive the new rules while preserving any user customizations.

Ported (5)

ID	Trigger	Purpose
read-before-edit	^(Edit|Write)\s	Reminder to Read a file before editing it
test-after-change	^(Edit|Write)\s.*(\.test\.|...)	Run tests after code edits
git-push-safety	git push|gh pr create	Fetch+rebase before push; --force-with-lease
git-merge-verify	gh pr merge|git merge	Verify CI + cleanup branch
instinct-downvote	/downvote|wrong instinct|...	Prompt /downvote on negative feedback (adapted from fs-cortex /cx-downvote to Sinapsis's native /downvote)

Skipped as duplicates (5)

env-never-commit, git-commit-quality, api-auth-check (→ api-auth-reminder), security-headers (→ security-headers-check), capture-decision (→ decision-capture). Sinapsis equivalents kept as-is.

Changes

• seeds/reflexes.json (new): 5 rules + _credit / _license header.
• core/_reflex-merge.mjs (new, ~100 LOC Node.js): idempotent merger, user id wins on conflict, atomic tmp → rename write that preserves 0600 file mode (install.sh hardens _passive-rules.json to 0600; the merger must not relax to umask). CLI flags: --seeds-path, --index-path, --dry-run.
• install.sh + install.bat: new Step 5c runs the merger after hook scripts.
• tests/test-reflexes.sh (new): 11 TDD tests including activator-integration (rules actually fire) and a regression guard that test-after-change does NOT fire on Read/Grep.

Codex review fixes applied pre-commit

/codex:review --base main flagged 3 issues, all addressed before this PR:

• P1 install.bat was missing the reflex step → Windows fresh installs would have stayed on the old rule set. Fixed.
• P2 atomic write replaced 0600-protected file with a new file at umask default (0644 typical) → relaxed permissions on a file documented as personal data. Fixed: merger stats existing file and chmods tmp to same mode (0600 fallback on fresh install).
• P2 test-after-change fired on Read/Grep because trigger only tested filename. Scoped to ^(Edit|Write)\s.*. Regression test added.

Test plan

• bash tests/test-reflexes.sh → 11/11 GREEN (including regression guard)
• Full suite → 127/127 GREEN, 0 regressions
• JSON validity on seeds/reflexes.json
• bash -n syntax on install.sh
• Manual: each new rule fires on its trigger (Edit, git push, gh pr merge, /downvote)
• Manual: test-after-change does NOT fire on Read/Grep
• /codex:review second-opinion applied

Independence

Branches from main (45949ed). No dependency on PR #7 (dashboard), PR #8 (seeds), or PR #9 (laws). Can merge in any order.

Credit

5 rules ported from fermontero/fs-cortex — MIT © 2026 Fernando Montero. Attribution preserved as origin: seed:fermontero-fs-cortex in each rule.

[Luispitik]

Verified empirically and the quality is above the bar: your 11 tests pass 11/11 on Windows Git Bash (Node 24), cygpath/mktemp/USERPROFILE are handled correctly, the merger works against main's real _passive-rules.json (6→11), all 5 rules fire through the v4.6.1 activator (byte-identical to your base — no functional drift), and the atomic write even preserves the file's 0600 mode. Scope is fine too: the passive-rules tier is core product (6 default rules documented in FEATURES.md), not engineering tooling.

The blocker is staleness, not substance — git merge-tree confirms conflicts in 4 files (CHANGELOG.md, docs/FEATURES.md, install.sh, install.bat), and v4.5.0 was meanwhile released in main for the Opus 4.7 integration, so the version number collides semantically as well. Asks:

1. Rebase onto main (v4.6.1) — when resolving install.sh/install.bat, keep the _precompact-guard.sh copy and the hook-count text that v4.5 introduced.
2. Renumber to the next free version and update the 'v4.5' references in _reflex-merge.mjs, seeds/reflexes.json, both installers and docs/FEATURES.md. Refresh the '116 → 127 passing' badge — the suite has grown since your base.
3. Register the tests in CI: add a bash tests/test-reflexes.sh step to .github/workflows/tests.yml (the existing ubuntu/macos/windows matrix is ideal for validating the cygpath handling).
4. Drop (or justify and downgrade) read-before-edit: Claude Code already enforces Read-before-Edit at the harness level, so the rule injects ~25 redundant tokens on every Edit/Write and occupies 1 of the activator's 3 slots — a single Edit on route.ts already saturates the cap (verified: api-auth-reminder + read-before-edit + test-after-change).
5. Create the tmp file already protected: fs.writeFileSync(tmp, text, { mode: 0o600 }) instead of write-then-chmod — closes the umask window on a file install.sh documents as personal data.
6. Minor: unify the Step 5c vs Step 5d comment inconsistency after the rebase, and have install.bat check errorlevel after invoking the merger and WARN on failure (install.sh's || true degrades gracefully, but silently — a one-line warning would help).
7. Found while testing: instinct-downvote is nearly inert — the activator is PreToolUse and only sees tool_name/tool_input, never the user's chat, so in practice it fires only when the user already ran /downvote (via file_path commands/downvote.md), making the inject redundant. Prune it or rethink the trigger during the rebase. Same spirit for test-after-change: it fires before the edit, so wording like "You are about to modify test/route code — plan to run the suite after" is more honest about the moment of injection.

After the rebase this merges. Thanks for the cross-OS care — it shows.

[Luispitik]

Ping @NestorPVsf — same situation as #9: substance was verified above the bar in the 2026-06-10 review, the blocker is only staleness (rebase onto main — now v4.6.2 —, renumber, CI registration, plus the smaller asks). If you don't have bandwidth, tell us and we'll close and track it in an issue; default in ~2 weeks if there's no activity.