fix(3610): unblock fresh Codex install when leftover bundled hooks present

`npx get-shit-done-cc@latest --codex` aborted with
"installer migration blocked pending user choice" listing 12 hooks/gsd-*
files. Those files are part of the GSD npm distribution
(hooks/gsd-prompt-guard.js, hooks/gsd-context-monitor.js, etc.), not
user-owned content, so asking the user to choose between keep/remove for
them was a UX bug, not a real choice. The installer is about to write
the fresh bundled versions in their place.

Root cause: `classifyPromptUserAction` in
get-shit-done/bin/lib/installer-migration-report.cjs knew two
unambiguous categories (`stale-sdk-build-artifact`, `user-facing-skill`)
but had no rule for the bundled GSD hooks. The first-time-baseline scan
classified them as `stale-gsd-looking` prompt-user blockers, and
`assertInstallerMigrationsUnblocked` threw.

A second gate compounded the bug: the safe-default resolver in
bin/install.js was wrapped in `if (!_migrationIsTty)`, so even with a
correct classification rule, TTY runs (every `npx get-shit-done-cc`
invocation) skipped the resolver and went straight to the hard throw.

Fix:
1) Add `hooks/gsd-<name>.(js|sh|cjs|mjs)` to `classifyPromptUserAction`
   as `bundled-gsd-hook` → `remove`. The regex is anchored at the
   top-level `hooks/` directory so nested paths like
   `hooks/gsd-helpers/index.js` (or any user-owned helper directory) do
   NOT auto-classify.
2) Remove the `!_migrationIsTty` gate from the resolver call in
   bin/install.js. The classifier-based path is unambiguous and must
   apply regardless of TTY; the env-override branch
   (GSD_INSTALLER_MIGRATION_RESOLVE) still applies only when isTty=false
   inside the resolver, preserving the #3541 semantic.

Regression test added
(tests/bug-3610-installer-migration-bundled-hooks-classification.test.cjs):

- Positive: hooks/gsd-*.{js,sh} → category=bundled-gsd-hook, choice=remove.
- Counter-test: hooks/my-custom-hook.js → classifier returns null
  (user files are preserved).
- Boundary: hooks/gsd-helpers/index.js → classifier returns null
  (nested directories don't auto-classify).
- End-to-end: 12 reporter-exact bundled hooks + empty manifest →
  resolver clears every blocker, assertInstallerMigrationsUnblocked
  does not throw.

Test exercises the real installer-migration code path
(`runInstallerMigrations` + `resolveInstallerMigrationPromptsForNonTty`
+ `assertInstallerMigrationsUnblocked`) — no source-grep, no raw text
matching on outputs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.changeset/3610-codex-install-bundled-hooks-blocker.md

@@ -0,0 +1,5 @@
+---
+type: Fixed
+issue: 3610
+---
+**Fresh `npx get-shit-done-cc@latest --codex` no longer hard-aborts when leftover bundled `hooks/gsd-*` files are present** — `classifyPromptUserAction` in `installer-migration-report.cjs` now recognizes the bundled GSD hooks (`hooks/gsd-<name>.{js,sh,cjs,mjs}`) as a known category (`bundled-gsd-hook`) and resolves them to `remove` so the installer can write the fresh bundled versions. The classifier-based safe-default resolver in `bin/install.js` now runs regardless of TTY state — gating it on `!isTTY` made interactive installs throw `installer migration blocked pending user choice` for files that have no actual user choice to make.