refactor: consolidate shared regex patterns and token validation

- Create src/utils/regex-patterns.ts with ANSI_ESCAPE_PATTERN_FULL,
  ANSI_ESCAPE_PATTERN_SIMPLE, TOKEN_PATTERN, and helper functions
- Create src/utils/token-validation.ts with MAX_SESSION_TOKENS and
  validation utilities
- Update session.ts, respawn-controller.ts, ai-checker-base.ts,
  ralph-tracker.ts, state-store.ts to use shared utilities
- Export all new utilities from src/utils/index.ts

Reduces code duplication while maintaining pre-compiled patterns
for performance.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/utils/index.ts

@@ -10,3 +10,17 @@ export { BufferAccumulator } from './buffer-accumulator.js';
 export { LRUMap, type LRUMapOptions } from './lru-map.js';
 export { CleanupManager, type TimerOptions } from './cleanup-manager.js';
 export { StaleExpirationMap, type StaleExpirationMapOptions } from './stale-expiration-map.js';
+export {
+  ANSI_ESCAPE_PATTERN_FULL,
+  ANSI_ESCAPE_PATTERN_SIMPLE,
+  TOKEN_PATTERN,
+  createAnsiPatternFull,
+  createAnsiPatternSimple,
+  stripAnsi,
+  stripAnsiSimple,
+} from './regex-patterns.js';
+export {
+  MAX_SESSION_TOKENS,
+  validateTokenCounts,
+  validateTokensAndCost,
+} from './token-validation.js';