fix(hooks): reuse compiled Codex matchers

.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)` 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. Runtime matching still contains an invalid regex as a non-match, so a direct library caller never throws into the loop.
+- **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.
 - **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.