refactor: consolidate formatting utilities and add testing infrastructure

- Replace 8 duplicate formatCurrency functions with shared utility
- Add comprehensive formatter utilities (currency, date, number, etc.)
- Set up Vitest for unit testing with 38 passing tests
- Set up Playwright for E2E testing
- Consolidate database connection to single source (src/utils/db.ts)
- Add auth middleware helpers to reduce code duplication
- Fix display bug: remove spurious minus sign in recent activity amounts
- Add path aliases for cleaner imports ($utils, $models)
- Add project documentation (CODEMAP.md, REFACTORING_PLAN.md)

Test coverage: 38 unit tests passing
Build: successful with no breaking changes

src/routes/api/fitness/seed-example/+server.ts

@@ -0,0 +1,64 @@
+import { json } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { dbConnect } from '$utils/db';
+import { WorkoutTemplate } from '../../../../models/WorkoutTemplate';
+
+// POST /api/fitness/seed-example - Create the example workout template
+export const POST: RequestHandler = async ({ locals }) => {
+  const session = await locals.auth();
+  if (!session || !session.user?.nickname) {
+    return json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  try {
+    await dbConnect();
+
+    // Check if example template already exists for this user
+    const existingTemplate = await WorkoutTemplate.findOne({
+      name: 'Push Day (Example)',
+      createdBy: session.user.nickname
+    });
+
+    if (existingTemplate) {
+      return json({ message: 'Example template already exists', template: existingTemplate });
+    }
+
+    // Create the example template with barbell squats and barbell bench press
+    const exampleTemplate = new WorkoutTemplate({
+      name: 'Push Day (Example)',
+      description: 'A sample push workout with squats and bench press - 3 sets of 10 reps each at 90kg',
+      exercises: [
+        {
+          name: 'Barbell Squats',
+          sets: [
+            { reps: 10, weight: 90, rpe: 7 },
+            { reps: 10, weight: 90, rpe: 8 },
+            { reps: 10, weight: 90, rpe: 9 }
+          ],
+          restTime: 120 // 2 minutes
+        },
+        {
+          name: 'Barbell Bench Press',
+          sets: [
+            { reps: 10, weight: 90, rpe: 7 },
+            { reps: 10, weight: 90, rpe: 8 },
+            { reps: 10, weight: 90, rpe: 9 }
+          ],
+          restTime: 120 // 2 minutes
+        }
+      ],
+      isPublic: false,
+      createdBy: session.user.nickname
+    });
+
+    await exampleTemplate.save();
+    
+    return json({ 
+      message: 'Example template created successfully!', 
+      template: exampleTemplate 
+    }, { status: 201 });
+  } catch (error) {
+    console.error('Error creating example template:', error);
+    return json({ error: 'Failed to create example template' }, { status: 500 });
+  }
+};