fix(agent-hooks): make hook remove() a no-op when nothing is managed

[bbingz]

fix(agent-hooks): make hook remove() a no-op when nothing is managed (six services)

Stacked on #9416 (reuses its no-op write machinery — updateHooksJsonWithRetry's
null-mutate). Its base branch orca/claude-config-dir-hooks is already pushed as PR
#9416; review the two commits after that PR's tip (a5826ea24d):
3e2e7e9598 (the six-service no-op change) and 804368b323 (review follow-up —
hermes enabled-membership gate + grok GROK_HOME test isolation). Refs #9414.

Bug

On a pristine machine (an agent CLI was never installed), toggling agent hooks OFF
runs each hook service's remove(). Six services — cursor, gemini, grok, command-code,
droid (Factory), and hermes — created their config dir + settings file from scratch
instead of doing nothing:

• The read primitives treat a missing file as empty (readHooksJson() returns {},
  readConfigFile() returns { ok: true, config: {} }).
• The services then wrote unconditionally. Both write primitives call
  mkdirSync(dir, { recursive: true }) before anything else
  (hooks-json-file.ts:writeHooksJson, hermes/hook-service.ts:writeConfigFile), so a
  remove() on a home that never had the agent installed would create e.g. ~/.cursor/,
  ~/.gemini/, ~/.grok/, ~/.commandcode/, ~/.factory/, or ~/.hermes/ plus its
  settings file.

The same unconditional write also reformatted a user settings file that held no managed
entries and rolled its .bak, even though Orca had nothing to remove.

remove() must be a strict no-op when there is nothing managed to remove: no dir creation,
no file creation, no reformat of a user file without managed entries, no backup roll.

Repro

1. Start from a home where the agent CLI has never run (no ~/.cursor, ~/.gemini, … —
   whichever service).
2. Toggle that agent's Orca status hooks OFF (the settings UI calls the service's
   remove()).
3. Before this fix: the config dir + an Orca-serialized settings file appear from nowhere.
   After this fix: nothing is created or touched.

Fix

Apply the same no-op contract #9416 gave Claude/OpenClaude:

• Five Claude-shaped JSON services (cursor, gemini, grok, command-code, droid) route
  their removal through updateHooksJsonWithRetry's null-mutate. The mutate strips managed
  commands from every event, and returns null when no managed hook is present — which
  skips the write entirely (no dir/file creation, no reformat, no .bak roll) and, as a
  bonus, gives remove() the same concurrent-writer stale-check install() already uses.
  Managed presence is detected with hookDefinitionHasManagedCommand (matches by managed
  script filename, so it still sweeps stale managed entries from older builds).
• Hermes (bespoke YAML write path) gates writeConfigFile on whether orca-status is
  actually in plugins.enabled — the only key disablePlugin() removes. The managed plugin
  dir is still deleted independently (rmSync), but the config.yaml write no longer keys
  off the plugin files: gating on those would recreate a config.yaml Orca had deleted, or
  reformat + .bak-roll a user file that never enabled orca-status, after the plugin dir
  is gone. Membership is checked directly (not via getConfigEnablement()) so a malformed
  plugins.disabled cannot mask an enabled orca-status.

No other refactoring; the install / status / remote paths are untouched.

Per-service verdict

Service	Config file	Had the bug?	Fix
cursor	~/.cursor/hooks.json	Yes	updateHooksJsonWithRetry null-mutate
gemini	~/.gemini/settings.json	Yes	updateHooksJsonWithRetry null-mutate
grok	$GROK_HOME/hooks/orca-status.json (or ~/.grok/…)	Yes	updateHooksJsonWithRetry null-mutate
command-code	~/.commandcode/settings.json	Yes	updateHooksJsonWithRetry null-mutate
droid (Factory)	~/.factory/settings.json	Yes	updateHooksJsonWithRetry null-mutate
hermes	~/.hermes/config.yaml (+ plugin dir)	Yes	write config.yaml only when orca-status is in plugins.enabled

All six were bugged; none were already safe.

Tests

Per service, three remove() tests (mirroring the Claude no-op tests on the base branch),
all using injected/mocked home dirs — no real ~/.* touched:

1. pristine home → remove() creates neither the config dir nor the settings file
   (state not_installed).
2. user file without managed entries → stays byte-identical (deliberately non-Orca
   serialization: tabs / no trailing newline) and no .bak is written.
3. real install → remove → managed entries stripped, user-authored entries preserved.

Repro-first check: the no-op tests were confirmed failing against the pre-fix source
(verified by reverting one service to base) and passing with the fix.

Review-round hardening

A follow-up review flagged two real gaps in the first cut, now fixed:

• Hermes partial-install write — the original pluginManaged || enabled gate captured
  pluginManaged before the plugin rmSync, so remove() on a managed-plugin home with a
  missing or unrelated config.yaml still created/reformatted it. Fixed by gating purely on
  orca-status ∈ plugins.enabled. Two regression tests were added (managed plugin + deleted
  config.yaml; managed plugin + byte-irregular user YAML) — both fail on the old gate, pass
  on the new one.
• Grok test isolation — getConfigPath() honors $GROK_HOME over the mocked homedir(),
  so an ambient GROK_HOME would have let the grok suite install/remove against the real
  Grok config. The suite now saves, clears, and restores GROK_HOME in beforeEach/afterEach.
• The Hermes pristine test now points HERMES_HOME at a not-yet-existing dir and asserts the
  config root is never created; the install→remove test preseeds user content (model, an
  unrelated enabled plugin) and asserts it survives.

Verification

• tsc --noEmit -p tsconfig.node.json (covers src/main/**/*, incl. the tests): no errors.
• oxlint on the touched files: clean (grok stays under the 300-line max-lines cap —
  no disable added).
• vitest run on the six hook-service.test.ts files: 40 passed / 0 failed / 5 skipped
  (Windows-only #6078 cases).
• Not independently re-run this round: the full test suite, adjacent importer suites,
  and Windows-only cases (the 5 skipped).