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>

AGENTS.md

@@ -31,6 +31,14 @@
 - Framework: Vitest with `node` environment.
 - Test file pattern: `src/**/*.test.ts`.
 - Keep tests near the code they cover; use `src/tests/stubs` for runtime stubbing.
+- For every user-facing feature or behavior change, add/update Playwright e2e coverage under `e2e/`.
+- When work is tied to a Gitea issue, record an e2e run video and upload it to that issue.
+  - One-off video run: `PW_VIDEO_MODE=on PW_TRACE_MODE=on bunx playwright test <spec>`
+  - Prefer comment-level attachments: post a comment first, then upload the video to that comment.
+    - Create comment: `tea comment -l <login> -r <owner>/<repo> <issue-index> "<message>"`
+  - Upload with `curl` (example, `tea api` in this repo's toolchain does not send multipart correctly):
+    - `TOKEN=$(awk '/- name: cloud.campbellwireless.net/{f=1} f && $1=="token:"{print $2; exit}' "$HOME/Library/Application Support/tea/config.yml")`
+    - `curl -fsS -X POST "https://cloud.campbellwireless.net/git/api/v1/repos/{owner}/{repo}/issues/comments/{comment_id}/assets" -H "Authorization: token $TOKEN" -F "name=<filename>" -F "attachment=@<path>"`
 
 ## Commit & Pull Request Guidelines
 - Commit messages currently follow a light “scope) message” pattern, e.g.,