feat(claudecode): follow the DirectoryAdded event, documented hook handler fields, and skill background

[dyoshikawa]

Background

Related issue: #2397 (partial — this PR covers gaps 1, 2, 3 and 5; gaps 4 and 6 follow separately)

Claude Code added a DirectoryAdded hook event, documents a set of per-handler hook fields that rulesync silently dropped on generate, lists two more events as taking no matcher, and added a background skill frontmatter field. Each was verified against the hooks docs, the skills docs and the upstream CHANGELOG before implementing.

Changes

DirectoryAdded (gap 1). Added as canonical directoryAdded plus the Claude mapping. The event is announced in the 2.1.219 changelog ("fires after /add-dir or the SDK register_repo_root control request registers a new working directory mid-session") but has no row in the docs' event table yet, so its matcher support is unknown and it is treated as no-matcher — a matcher authored on it is dropped with the existing warning rather than written into settings.json to be ignored. Noted in a code comment.

Dropped handler fields (gap 2). args, async, asyncRewake, shell, statusMessage, once and continueOnBlock now generate and import for claudecode and claudecode-plugin (which shares the converter config). asyncRewake and continueOnBlock are new on the canonical HookDefinitionSchema; the rest already existed. The boolean and string passthrough unions widened accordingly.

applyCommandPrefix no longer rewrites command when the exec form is in use: with args present the tool spawns command directly, with no shell to expand $CLAUDE_PROJECT_DIR or strip the quotes the prefix adds, so the prefixed string would be looked up as a literal file name. The check is gated on the converter actually emitting args, so shell-form hooks and other tools are unaffected — verified both branches.

Missing no-matcher events (gap 3). beforeSubmitPrompt (→ UserPromptSubmit) and stop added to CLAUDE_NO_MATCHER_EVENTS, matching the docs' matcher table.

Skill background (gap 5). Added to the Claude Code skill frontmatter schema and the claudecode section of the rulesync skill schema, carried as a defined field rather than a truthy one — background: false is the whole point, and a truthy check would drop it. Applies to claudecode-plugin too, since ClaudecodePluginSkill extends ClaudecodeSkill.

Deferred to follow-up PRs

• Gap 4 (rulesync emits the Write(path) / NotebookEdit(path) / Glob(path) forms Claude Code warns about) — confirmed against the docs and worth fixing, but it changes generated permission output and deserves its own diff.
• Gap 6 (sandbox.* authorable through the claudecode permissions override) — a new public override surface that Claude Code permissions: support permissions.defaultMode and permissions.additionalDirectories (and note sandbox.*) #2129 deliberately deferred.

This PR therefore does not close #2397.

Verification

• pnpm cicheck (full: code + content)
• npx vitest run --config vitest.e2e.config.ts src/e2e/e2e-hooks.spec.ts src/e2e/e2e-skills.spec.ts
• Manual generate/import round trips for hooks and skills in a scratch project.