feat(polling-contracts): add generic polling interface with TypeScript types and Zod schemas

- Add @timesafari/polling-contracts package with comprehensive type definitions
- Implement GenericPollingRequest, PollingResult, and PollingScheduleConfig interfaces
- Add Zod schemas for StarredProjectsRequest/Response and DeepLinkParams validation
- Include calculateBackoffDelay utility with unified retry policy (exponential, linear, fixed)
- Add OutboxPressureManager for storage pressure controls and back-pressure signals
- Implement TelemetryManager with cardinality budgets and PII redaction
- Add ClockSyncManager for JWT timestamp validation and skew tolerance
- Include comprehensive unit tests with Jest snapshots and race condition testing
- Add JWT_ID_PATTERN regex for canonical JWT ID format validation
- Support idempotency with X-Idempotency-Key enforcement
- Implement watermark CAS (Compare-and-Swap) for race condition prevention

This establishes the foundation for the new generic polling system where host apps
define request/response schemas and the plugin provides robust polling logic.

packages/polling-contracts/tsconfig.json

@@ -0,0 +1,31 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "lib": ["ES2020"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "removeComments": false,
+    "noImplicitAny": true,
+    "noImplicitReturns": true,
+    "noImplicitThis": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "exactOptionalPropertyTypes": true
+  },
+  "include": [
+    "src/**/*"
+  ],
+  "exclude": [
+    "node_modules",
+    "dist",
+    "**/__tests__/**"
+  ]
+}