ci: run npm test and the hooks against a released ix

[KageBinary]

Audit remediation PL-03.

What changes

• mcp build job: adds npm test (the mock-ix suite; the mock is bash, so it stays on Linux). The existing "Committed dist matches the build" step already rebuilds and fails on any mcp/dist drift (including untracked emit), so no second dist check was added.
• New real ix job: installs ix v0.12.0 from the release tarball (sha256sum -c against the .sha256 sidecar), Node 22, ripgrep; IX_ENDPOINT=http://127.0.0.1:1, IX_NO_UPDATE_CHECK=1; runs npm run test:real-ix. CI Passed now needs it.
• mcp/tests/real-ix/hooks.real-ix.ts (+ its committed dist emit, since tsc compiles tests into mcp/dist). Named *.real-ix.ts so npm test does not pick it up.

What the real-ix test asserts

Hooks are run exactly as Cursor runs them: the node "${CURSOR_PLUGIN_ROOT}/mcp/dist/hooks/*.js" commands from hooks/hooks.json, with IX_BIN unset so the real ix on PATH is used, temp HOME/IX_HOME/XDG_STATE_HOME.

1. ix --version is the pinned release.
2. parseIxJson reads ix's real workspace_not_mapped error record (exit 1, JSON on stdout).
3. postToolUse Grep, unmapped dir: locate's error record is not read as a symbol; ripgrep hits from ix text still reach additional_context; output keys are ones Cursor reads.
4. postToolUse Write, unmapped: ix impact's exit-1 error body is parsed and the hook stays silent.
5. Backend unreachable (workspace registered): all six hook entry points exit 0, inside their hooks.json timeouts, with only Cursor-documented output fields; no auto-map stamp written.
6. Every ix argv the hooks actually ran (from the plugin's own IX_DEBUG_LOG), plus the two auto-map argv and pre-search's optional --path/--language, is accepted by this CLI: no unknown option. Checked locally that a CLI rejecting --silent turns this test red.

No version fields changed.

🤖 Generated with Claude Code

https://claude.ai/code/session_01EqMeW5huGYgRUWS2TtuvF8

[KageBinary]

Reviewed against the released ix v0.12.0. Fixed in a0066a3:

• Pinned the tarball's sha256 in the workflow.
• The Grep path was the project root, so pre-search sent no --path, and no payload had a type. --path and --language were only checked against a hand-written argv list. A scoped Grep (lib/, ts) now makes the hook send both, and the test requires them among the argv it actually ran; renaming --language now fails 2 tests.

Note: the status and map argv lists are still hand-written. Real-ix 7/7 and npm test 27/27 on Node 22; CI is green. Merging.