Add Playwright e2e coverage + comment-level video upload workflow (#40)

## Summary
- add Playwright e2e auth setup + seeded test DB flow
- fix Playwright startup order so DB seed runs before web server uses SQLite
- add full trip-planning e2e scenario (future trip, travellers, destination, flight, lodging, upcoming verification)
- configure Auth.js custom sign-in page for base-path routing
- add repo guidance in AGENTS.md / CLAUDE.md requiring e2e for user-facing changes
- document and validate comment-level Gitea video attachment workflow (create comment, upload to comment assets endpoint)

## Validation
- bunx playwright test e2e/auth.test.ts --project=chromium\n- bunx playwright test e2e/trip-planning.test.ts --project=chromium
- PW_VIDEO_MODE=on PW_TRACE_MODE=off bunx playwright test e2e/trip-planning.test.ts --project=chromium

## Issue
- relates to #38

Co-authored-by: AI Agent <ai-agent@campbellwireless.net>
Reviewed-on: #40
Co-authored-by: Shaun Campbell <shaun@campbellwireless.net>
Co-committed-by: Shaun Campbell <shaun@campbellwireless.net>

vite.config.ts

@@ -5,6 +5,6 @@ import { defineConfig } from 'vite';
 export default defineConfig({
 	plugins: [tailwindcss(), sveltekit()],
 	server: {
-		allowedHosts: ['cloud.campbellwireless.net']
+		allowedHosts: ['cloud.campbellwireless.net', '127.0.0.1', 'localhost']
 	}
 });