test: add unit test coverage for services and lib

- 255 tests across 14 files (was 70 tests in 4 files)
- src/services/__tests__: auth (registerUser, updateUserPassword, updateUserProfile), okrs (calculateOKRProgress, createOKR, updateKeyResult, updateOKR), teams (createTeam, addTeamMember, isAdminOfUser, getTeamMemberIdsForAdminTeams, getUserTeams), weather (getPreviousWeatherEntriesForUsers, shareWeatherSessionToTeam, getWeatherSessionsHistory), workshops (createSwotItem, duplicateSwotItem, updateAction, createMotivatorSession, updateCardInfluence, addGifMoodItem, shareGifMoodSessionToTeam, getLatestEventTimestamp, cleanupOldEvents)
- src/lib/__tests__: date-utils, weather-utils, okr-utils, gravatar, workshops, share-utils
- Update vitest coverage to include src/lib/**

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

vitest.config.ts

@@ -0,0 +1,23 @@
+import { defineConfig } from 'vitest/config';
+import tsconfigPaths from 'vite-tsconfig-paths';
+
+export default defineConfig({
+  plugins: [tsconfigPaths()],
+  test: {
+    environment: 'node',
+    globals: true,
+    coverage: {
+      provider: 'v8',
+      include: ['src/services/**/*.ts', 'src/lib/**/*.ts'],
+      exclude: [
+        'src/services/__tests__/**',
+        'src/lib/__tests__/**',
+        'src/services/database.ts',
+        'src/lib/types.ts',
+        'src/lib/auth.ts',
+        'src/lib/auth.config.ts',
+      ],
+      reporter: ['text', 'html'],
+    },
+  },
+});