feat(cli): merge plugin hooks into antigravity's .agents/hooks.json

[tkman59]

🎯 What & why

aidd setup --ai antigravity now installs the AIDD memory hook: agy refreshes the project memory at session start. Phase 3 of #511, stacked on #957.

🛠️ How it works

• Route. The memory hook reaches a project through the aidd-context plugin, not through HooksCapability. Codex's HooksCapability is never fed: no codex-hooks config ref exists, so copying it would have written nothing. Antigravity uses the project-hooks route Cursor already had, with idempotent merge, per-entry provenance and safe clean.
• Generalisation, Cursor unchanged. A tool now declares a ProjectHooksFormat beside hooksDestination: "project", which flat mode may now declare too. project-hooks-materializer.ts and remove-project-hooks.ts read only that format, with no Cursor import left. Cursor's suites pass with no assertion changed.
• Antigravity format (antigravity-hooks.ts):
  • one key per plugin, handlers directly under SessionStart;
  • scripts copied to .agents/hooks/<plugin>/;
  • every command prefixed with cd .. && ;
  • other events skipped with a warning;
  • translate --to antigravity --as flat uses the same merge function; hooksMerge now receives the plugin name.
• Measured on agy 1.2.17, with an interactive session under a pty (script -q /dev/null agy -i … --add-dir <ws>). In print mode the model is never called, so no hook fires.
  • Claude's nested [{ "hooks": [...] }] is rejected: invalid hook "aidd-probe": command hook must specify 'command'.
  • A workspace hook runs from <repo>/.agents, through a shell. A probe hook logged "cwd":".../agy-cwd-probe/.agents" with "workspacePaths":[".../agy-cwd-probe"]. With cd .. && , the marker read AIDD-MEMORY-MARKER cwd=<repo> docs=true.
• Safety. An unparsable .agents/hooks.json now stops the install with the file named (.agents/hooks.json is not valid JSON (…); left untouched.), for Cursor too.

🧪 How to verify

• cd cli && pnpm test: 6835 passed, 1 skipped. pnpm smoke: 144 passed, 0 failed.
• Real run in a temp git repo (with aidd_docs/memory/ and AGENTS.md carrying the memory markers):
  1. aidd setup --source local --path <framework> --ai antigravity --plugins recommended --yes writes .agents/hooks.json with the aidd-context key and .agents/hooks/aidd-context/update_memory.js.
  2. Add a user key lint, then run setup again: .agents/hooks.json is byte-identical.
  3. script -q /dev/null agy -i "reply OK" --add-dir <repo> logs loaded 2 named hooks from 1 hooks.json file(s), and AGENTS.md at the repo root gains the memory list.
  4. aidd clean --force leaves .agents/hooks.json holding only lint, and removes .agents/hooks/.
• Golden: only the antigravity:flat cell moved (.agents/hooks.json and the copied script).

⚠️ Heads-up

• No CI runtime proof: a turn needs a Google login, and print mode fires no hook on 1.2.17.
• The second setup in the real run was a no-op ("already installed"). Re-merge idempotence is proven by the unit test.
• Diff is about 540 lines of code and tests, plus about 65 lines of plan. The generalisation was not split out, because alone it has a single user.
• Out of scope, worth an issue: Codex's HooksCapability and mergeCodexHooksJson are dead code.

🔗 Linked issue

Refs #511

✅ I certify

• I DO CERTIFY I READ EACH LINE OF THE PULL REQUEST BECAUSE I AM A SOFTWARE ENGINEER, NOT A AI PUPPY.

🤖 Generated with Claude Code