docs(ai): add lessons for browser test output and shared storage

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.ai/lessons.md

@@ -5,6 +5,7 @@
 - When a symptom matches an earlier fix, inspect that fix and prove why it no longer works before adding another workaround.
 - Test old reports against the current branch because later changes can make the report obsolete.
 - Use the same regression test before and after the production change so the result shows the behavior difference.
+- Redirect browser test output to a file (`> /tmp/x.log 2>&1`); piping it (`| tail`) hangs because the Playwright server keeps the pipe open.
 - Call `visit()` directly in each `tests/v4/Browser` test body; Pest does not mark a test that only uses helper-wrapped `visit()` as a browser test, so it fails with `sendText() on null`.
 
 ## Verify the complete user flow
@@ -68,6 +69,7 @@
 - Deployment shell commands run in the Alpine/BusyBox helper image and pass through the non-root sudo parser. Verify new flags and shell syntax in that image and with `parseCommandsByLineForSudo()`; faked command output hides both failures.
 - Put multi-step remote shell logic in one `sh -c '<script>' sh <args>` line. The non-root parser then only puts sudo in front of it; it rewrites `x=$(...)`, `&&`, `|` and shell keywords in any other line.
 - `Server` has an identity map. Tests that create servers in several dataset cases with `RefreshDatabase` must call `Server::flushIdentityMap()` in `beforeEach`/`afterEach`, or a case reads the cached server of the previous case.
+- Host test runs share `storage/` with the dev container. Fake the `ssh-keys`/`ssh-mux` disks and `Process` in tests that run seeders or write SSH files, or the test deletes/chowns the dev instance's SSH keys and SSH breaks for `www-data`.
 - Dev QEMU servers from `dev:qemu` are seeded, not validated: they have no `coolify` Docker network, and Alpine has no bash until `InstallPrerequisites` runs.
 
 ## Format only your own files