Add signal contracts for reachability, exploitability, trust, and unknown symbols

- Introduced `ReachabilityState`, `RuntimeHit`, `ExploitabilitySignal`, `ReachabilitySignal`, `SignalEnvelope`, `SignalType`, `TrustSignal`, and `UnknownSymbolSignal` records to define various signal types and their properties.
- Implemented JSON serialization attributes for proper data interchange.
- Created project files for the new signal contracts library and corresponding test projects.
- Added deterministic test fixtures for micro-interaction testing.
- Included cryptographic keys for secure operations with cosign.

tests/fixtures/micro/micro-fixtures.ts

@@ -0,0 +1,89 @@
+/**
+ * Micro-interaction test fixtures with deterministic seeds (MI8)
+ *
+ * Usage:
+ * - Import these constants in Storybook stories and Playwright tests
+ * - Use frozenTimestamp for all date operations
+ * - Use rngSeed for any randomized content
+ */
+
+// Frozen timestamp: 2025-12-04T12:00:00Z (as per advisory)
+export const FROZEN_TIMESTAMP = new Date('2025-12-04T12:00:00.000Z');
+export const FROZEN_TIMESTAMP_MS = 1733313600000;
+
+// Fixed RNG seed as per advisory: 0x5EED2025
+export const RNG_SEED = 0x5EED2025;
+
+// Deterministic UUID generator (seeded)
+export function seededUuid(seed: number = RNG_SEED, index: number = 0): string {
+  const hash = ((seed + index) * 2654435761) >>> 0;
+  const hex = hash.toString(16).padStart(8, '0');
+  return `${hex.slice(0, 8)}-${hex.slice(0, 4)}-4${hex.slice(1, 4)}-8${hex.slice(4, 7)}-${hex}0000`.slice(0, 36);
+}
+
+// Skeleton state fixture
+export const skeletonFixture = {
+  showAfterMs: 400,
+  loadingDurationMs: 1200,
+  state: 'loading' as const,
+  timestamp: FROZEN_TIMESTAMP,
+};
+
+// Error state fixture
+export const errorFixture = {
+  code: 'UI_ERR_001',
+  message: 'Failed to load data',
+  retryAvailable: true,
+  timestamp: FROZEN_TIMESTAMP,
+  correlationId: seededUuid(RNG_SEED, 1),
+};
+
+// Offline state fixture
+export const offlineFixture = {
+  isOffline: true,
+  lastOnline: new Date(FROZEN_TIMESTAMP_MS - 300000), // 5 minutes ago
+  cachedDataAge: 'less than 1 hour',
+  timestamp: FROZEN_TIMESTAMP,
+};
+
+// Toast/snackbar fixture
+export const toastFixture = {
+  id: seededUuid(RNG_SEED, 2),
+  type: 'info' as const,
+  message: 'Changes saved successfully',
+  undoAvailable: true,
+  undoWindowMs: 8000,
+  timestamp: FROZEN_TIMESTAMP,
+};
+
+// Reduced motion test config
+export const reducedMotionConfig = {
+  enabled: true,
+  emulateQuery: true,
+  dataAttribute: 'data-reduce-motion',
+  dataValue: '1',
+};
+
+// Playwright/Storybook timer config
+export const timerConfig = {
+  useFakeTimers: true,
+  now: FROZEN_TIMESTAMP_MS,
+  shouldAdvanceTime: false,
+};
+
+// Sample telemetry event
+export const sampleTelemetryEvent = {
+  schema_version: 'v1.0',
+  event_type: 'ui.micro.interaction',
+  timestamp: FROZEN_TIMESTAMP.toISOString(),
+  tenant_id: 'test-tenant',
+  surface: 'dashboard',
+  component: 'button',
+  action: 'click',
+  latency_ms: 45,
+  outcome: 'success',
+  reduced_motion: false,
+  offline_mode: false,
+  error_code: null,
+  correlation_id: seededUuid(RNG_SEED, 3),
+};