perf: implement phase 1-3 performance optimizations

Add implementation plans and code structure analysis for a 3-phase
performance optimization effort. Refactor core modules to reduce
timer overhead, consolidate regex usage, extract exec timeout config,
add debouncer utility, and streamline server/schema validation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/utils/index.ts

@@ -9,14 +9,19 @@
 export { BufferAccumulator } from './buffer-accumulator.js';
 export { LRUMap, type LRUMapOptions } from './lru-map.js';
 export { CleanupManager, type TimerOptions } from './cleanup-manager.js';
+export { Debouncer, KeyedDebouncer } from './debouncer.js';
 export { StaleExpirationMap, type StaleExpirationMapOptions } from './stale-expiration-map.js';
 export {
   ANSI_ESCAPE_PATTERN_FULL,
   ANSI_ESCAPE_PATTERN_SIMPLE,
   TOKEN_PATTERN,
   SPINNER_PATTERN,
+  createAnsiPatternFull,
+  createAnsiPatternSimple,
+  stripAnsi,
+  SAFE_PATH_PATTERN,
 } from './regex-patterns.js';
-export { MAX_SESSION_TOKENS } from './token-validation.js';
+export { MAX_SESSION_TOKENS, validateTokenCounts, validateTokensAndCost } from './token-validation.js';
 export { stringSimilarity, fuzzyPhraseMatch, todoContentHash } from './string-similarity.js';
 export { assertNever } from './type-safety.js';
 export { wrapWithNice } from './nice-wrapper.js';