refactor: consolidate ~70 scattered constants into 6 new config files (phase 6)

Create 6 domain-focused config files in src/config/ to centralize operational
tuning knobs that were scattered across 15+ source files:

- server-timing.ts: SSE batching, state debounce, scheduled runs, error recovery
- auth-config.ts: session TTL, rate limits, hook timeout
- tunnel-config.ts: QR token rotation, tunnel process lifecycle
- terminal-limits.ts: input length, terminal cols/rows, session name
- ai-defaults.ts: AI model string, idle/plan context limits
- team-config.ts: poll interval, cache sizes

Eliminates all cross-file duplicates:
- AI model string: 5 occurrences → 1 (config only)
- STATS_COLLECTION_INTERVAL_MS: 2 → 1
- timeout: 10000 in hooks-config: 6 → 0 (now HOOK_TIMEOUT_MS)
- MAX_TRACKED_AGENTS shadow: removed, imports from map-limits

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

src/index.ts

@@ -14,10 +14,10 @@ import { program } from './cli.js';
 // In web mode, we should NOT exit on transient errors — log and continue
 const isWebMode = process.argv.includes('web');
 
+import { MAX_CONSECUTIVE_ERRORS, ERROR_RESET_MS } from './config/server-timing.js';
+
 // Track consecutive unhandled errors in web mode — restart after too many
 let consecutiveErrors = 0;
-const MAX_CONSECUTIVE_ERRORS = 5;
-const ERROR_RESET_MS = 60000; // Reset counter after 1 minute of no errors
 let errorResetTimer: ReturnType<typeof setTimeout> | null = null;
 
 function trackError(): void {