fix(hooks): share matcher validation instances

.agents/notes/implemented/feature/2026-06-30-hook-protocol-lib.md

@@ -15,7 +15,7 @@ This Agent Note introduces `@deepseek-ai/dsh-hook-protocol`, a **library** (not
 A new `packages/hooks/` group with `hook-protocol` as a pure library. It owns four primitive families and the `hook/*` session events; each bridge plugin (`dsh-hooks-claude`, `dsh-hooks-codex`) owns what genuinely differs.
 
 **Shared (here):**
-- **Matcher** — `matcherDiagnostic(pattern, mode)`, `compileMatchers(patterns, mode)`, and `matchesMatcher(pattern, query, mode)`. Pure `[A-Za-z0-9_|]+` patterns use the shared exact-match fast path (pipe = alternatives); the ONE remaining dialect axis is collapsed to `mode`: other Claude patterns use JavaScript `RegExp`, while other Codex patterns use Rust `regex`, including Rust-only syntax such as `(?i)`. Match-all on absent/`''`/`'*'`. Each bridge ignores unsupported events before group parsing, discards matcher fields on supported events without matcher subjects, validates the remaining runnable groups, and treats an invalid regex there as a whole-config load failure, with a stable dialect/pattern/event diagnostic; no hook listeners are registered. For runtime, a bridge compiles its finite set of unique config patterns ONCE, reuses that set across hook points, and disposes it after detached runs drain on plugin teardown. This config-scoped ownership avoids a module-global cache while preventing repeated Rust/WASM construction from raising a non-shrinking memory high-water mark on every match. The one-shot predicate still contains an invalid regex as a non-match, so a direct library caller never throws into the loop.
+- **Matcher** — `compileMatchers(patterns, mode)`, `matcherDiagnostic(pattern, mode)`, and `matchesMatcher(pattern, query, mode)`. Pure `[A-Za-z0-9_|]+` patterns use the shared exact-match fast path (pipe = alternatives); the ONE remaining dialect axis is collapsed to `mode`: other Claude patterns use JavaScript `RegExp`, while other Codex patterns use Rust `regex`, including Rust-only syntax such as `(?i)`. Match-all on absent/`''`/`'*'`. Each bridge ignores unsupported events before group parsing, discards matcher fields on supported events without matcher subjects, collects the remaining runnable groups, and compiles their finite set of unique patterns ONCE. It reads validation diagnostics from that compiled registry: an invalid regex causes whole-config rejection after the registry is disposed, while a valid parse returns the SAME registry for hook-point matching and plugin-teardown disposal after detached runs drain. The stable diagnostic still names dialect/pattern/event and no hook listeners are registered on failure. This config-scoped ownership avoids both a module-global cache and separate validation/runtime Rust/WASM construction, whose non-shrinking allocator raises its memory high-water mark on every construction. The one-shot helpers remain contained, so a direct library caller never throws into the loop.
 - **Execution** — `runHook(bash, hook, options)`. Runs a command hook through the `ctx.bash` seam rather than a bespoke `spawn`: the executor already provides the scrubbed-but-overridable env, process-group kills, and timeout the protocol needs, and `dsh-bash`'s `stdin`/`env` fields (added for exactly this) are the trusted-plugin surface an in-process bridge is allowed to use. It serializes the bridge-built payload to stdin (trailing newline iff CC), honors the hook's `timeoutSec` (else `DEFAULT_HOOK_TIMEOUT_MS`, the 10-minute reference default both dialects share), and never throws (an executor rejection becomes a non-blocking-error `HookOutput`).
 - **Decode** — `parseHookOutput(exit, stdout, stderr)`, the exit-code + structured-stdout codec, producing a dialect-neutral `HookOutput`. Exit `0` → lenient JSON parse of stdout; exit `2` → blocking error with `stderr` as the reason (surfaced as `decision: 'block'` so no caller needs a separate exit-code branch); other → non-blocking error. Parses the CC structured-stdout fields that have a consumer on some path (`continue`/`stopReason`/`decision`/`hookSpecificOutput.{permissionDecision,additionalContext,updatedInput}`/`systemMessage`); the bridge honors only the subset meaningful for its dialect. Fields with no consumer on any path are not parsed at all (CC's `suppressOutput` — hook stdout never enters a transcript here, so there is nothing to suppress; see [the tighten-hook-protocol-contract Agent Note](../simplification/2026-07-04-tighten-hook-protocol-contract.md)).
 - **Merge** — `mergeHookOutputs(outputs)`, folding multiple matched hooks into one most-restrictive `MergedHookOutcome`: permission precedence **deny > ask > allow**, halt sticky on the first `continue:false`, block reasons joined `\n\n`, context/system-messages accumulated in order.