feat: add type-safe boundaries for analytics mock data with explicit …

[onyemaechiezekiel9]

Extract analytics mock data into a dedicated, type-safe module that enforces shape validation at compile time. MOCK_ANALYTICS_SUMMARY is now explicitly typed as AnalyticsSummary with the satisfies keyword, ensuring that any shape changes are caught by TypeScript before runtime.

Changes
New Files
lib/api/analytics/types.ts: Focused module boundary with type re-exports and runtime type guards (isAnalyticsSummary, isResourceAccessCount)
lib/api/analytics/mock.ts: Analytics fixture data with explicit typing and type-safe accessor functions
lib/api/analytics/mock.test.ts: Comprehensive test coverage (16 tests) for type safety and data consistency
Modified Files
lib/api/mock.ts:
Added imports from ./analytics/mock module
Removed generateMockMemberGrowth() function and MOCK_ANALYTICS_SUMMARY definition
Updated MockAccessApi.analytics methods to use accessor functions (getMemberGrowth(), getResourceAccess())
What's Fixed
Type Safety
MOCK_ANALYTICS_SUMMARY is now explicitly typed as AnalyticsSummary
Uses as const satisfies AnalyticsSummary for compile-time shape checking
Accessor functions return explicit types: AnalyticsSummary['resourceAccess'], not any
Focused Boundaries
Analytics data isolated in dedicated lib/api/analytics/ module
Clear separation of concerns: types, mock data, and tests
Type guards enable runtime validation when parsing external data
Backward Compatibility
Re-exports preserve existing import paths
MOCK_ANALYTICS_SUMMARY still exported for direct access
No changes to mock data values—structure only
Testing
16 tests verify:

Mock structure (resourceAccess field presence and array type)
AnalyticsSummary shape (all required fields present with correct types)
Accessor functions (return correct data with proper types)
Type safety (compile-time type assignments validate shape)
Data consistency (monotonic growth, count relationships, non-negative values)
All tests pass runtime validation and compile with TypeScript satisfies checking.

How to Test
bash

npm test # Run analytics mock tests
npm run typecheck # Verify TypeScript compilation
npm run build # Full build verification
Related Issue
Fixes #385: Add focused type-safe boundaries for analytics mock data

Acceptance Criteria Met
✅ AnalyticsSummary interface defined with explicit field types
✅ MOCK_ANALYTICS_SUMMARY explicitly typed as AnalyticsSummary
✅ satisfies AnalyticsSummary used for compile-time shape checking
✅ resourceAccess typed as AnalyticsSummary['resourceAccess'] (not any)
✅ Access functions have typed return values (not any/unknown)
✅ Analytics mock extracted to focused module
✅ All existing consumers receive same data shape
✅ TypeScript compilation succeeds
✅ All tests pass
✅ Mock data values unchanged (structure only)