feat(REQ-001): scaffold Ionic 8 + Angular 20 + Capacitor project

- Initialize Ionic tabs project with Angular 20 and Capacitor 8
- Configure 4-tab layout: Journal, Stats, Plans, Profile
- Create feature modules with lazy loading (home, stats, search, profile)
- Add core services stubs (meal, calorie-estimator, auth, storage)
- Add modal placeholders for manual and LLM input
- Apply Precision Vitality design system (colors, fonts, tonal layering)
- Configure Lexend + Plus Jakarta Sans typography
- Implement no-border design rule with tonal surface hierarchy
- Add food dictionary for AI calorie estimation
- Configure environment files with Firebase placeholders
- Set Capacitor appId: run.i_a.calorietracker
- Verify: ionic build and cap sync pass successfully

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

src/app/core/services/auth.service.ts

@@ -0,0 +1,7 @@
+import { Injectable } from '@angular/core';
+
+@Injectable({ providedIn: 'root' })
+export class AuthService {
+  // TODO: Implement in REQ-002 with Firebase Auth
+  constructor() {}
+}