fix(hooks): remove speculative regex runtime

.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** — `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 config registry: rejection disposes the registry before whole-config failure, while admission returns the SAME registry for hook-point matching and plugin-teardown disposal after detached runs drain. Codex valid instances and invalid diagnostics additionally use a versioned interner on the synchronous `rregex` CJS module, so one-shot calls and hook-protocol/Cordis reloads reuse them without putting state on `globalThis`. Because that dependency's WASM allocator does not shrink after `free()`, the interner deliberately retains at most `MAX_INTERNED_CODEX_REGEX_PATTERNS` (128) distinct non-literal patterns per process. At capacity, a new distinct pattern is rejected before native construction with a stable capacity/pattern/event diagnostic; known patterns remain usable and process restart resets the budget. The hard bound covers adversarial unique-pattern reloads without an unbounded cache, while direct library calls remain contained and never throw into the loop.
+- **Matcher** — `matcherDiagnostic(pattern, mode)` and `matchesMatcher(pattern, query, mode)`. The ONE axis the dialects differ on is collapsed to the `mode` parameter: `claude` treats a pure `[A-Za-z0-9_|]+` pattern as a literal (pipe = exact-match alternation) and anything else as a regex; `codex` is always an unanchored regex. 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.
 - **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.