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>

e2e/setup/seed-db.ts

@@ -0,0 +1,77 @@
+// Bun script — runs with `bun run e2e/setup/seed-db.ts`.
+// Uses bun:sqlite and argon2 directly; must NOT be imported from Node context.
+import { Database as BunSqlite } from 'bun:sqlite';
+import { existsSync, unlinkSync } from 'fs';
+import { resolve } from 'path';
+import argon2 from 'argon2';
+import { randomUUID } from 'crypto';
+import { config as dotenvConfig } from 'dotenv';
+import { TEST_USERS } from './test-users.js';
+
+dotenvConfig({ path: resolve(process.cwd(), '.env.test'), override: true });
+
+const DB_PATH = resolve(process.cwd(), 'trips.test.db');
+
+// Delete any existing test DB so we start clean each run
+for (const ext of ['', '-shm', '-wal']) {
+	const p = DB_PATH + ext;
+	if (existsSync(p)) {
+		unlinkSync(p);
+	}
+}
+
+const db = new BunSqlite(DB_PATH);
+db.exec('PRAGMA foreign_keys = ON');
+
+// Wrap bun:sqlite to match the Database interface expected by runMigrations
+const dbWrapper = {
+	run(sql: string, params: unknown[] = []) {
+		db.query(sql).run(...(params as [unknown?, ...unknown[]]));
+	},
+	get<T = Record<string, unknown>>(sql: string, params: unknown[] = []): T | undefined {
+		const row = db.query(sql).get(...(params as [unknown?, ...unknown[]]));
+		return (row === null ? undefined : row) as T | undefined;
+	},
+	all<T = Record<string, unknown>>(sql: string, params: unknown[] = []): T[] {
+		return db.query(sql).all(...(params as [unknown?, ...unknown[]])) as T[];
+	},
+	close() {
+		db.close();
+	}
+};
+
+const { runMigrations } = await import('../../src/lib/server/db/migrations.js');
+runMigrations(dbWrapper);
+console.log('[e2e] Migrations complete.');
+
+async function hashPassword(password: string): Promise<string> {
+	return argon2.hash(password, {
+		type: argon2.argon2id,
+		memoryCost: 8192,
+		timeCost: 2,
+		parallelism: 1
+	});
+}
+
+const regularId = randomUUID();
+dbWrapper.run(
+	`INSERT INTO users (id, username, full_name, email, auth_source) VALUES (?, ?, ?, ?, ?)`,
+	[regularId, TEST_USERS.regular.username, TEST_USERS.regular.fullName, TEST_USERS.regular.email, 'Local']
+);
+dbWrapper.run(`INSERT INTO local_credentials (user_id, password_hash) VALUES (?, ?)`, [
+	regularId,
+	await hashPassword(TEST_USERS.regular.password)
+]);
+
+const adminId = randomUUID();
+dbWrapper.run(
+	`INSERT INTO users (id, username, full_name, email, auth_source) VALUES (?, ?, ?, ?, ?)`,
+	[adminId, TEST_USERS.admin.username, TEST_USERS.admin.fullName, TEST_USERS.admin.email, 'Local']
+);
+dbWrapper.run(`INSERT INTO local_credentials (user_id, password_hash) VALUES (?, ?)`, [
+	adminId,
+	await hashPassword(TEST_USERS.admin.password)
+]);
+
+db.close();
+console.log(`[e2e] Seeded users: ${TEST_USERS.regular.username}, ${TEST_USERS.admin.username}`);