chore(ai-workflow): require cross-browser playwright checks

docs/agent-playbooks/hooks-setup.md

@@ -55,6 +55,8 @@ exit $status
 
 By default, `scripts/agent-hooks/verify.sh` exits non-zero when `corepack yarn build`, `corepack yarn lint`, or `corepack yarn type-check` fails. Set `AGENT_VERIFY_MODE=advisory` only when you intentionally need signal from a broken tree without blocking the hook.
 
+Lifecycle hooks do not replace manual browser verification. For UI or visual changes, still run `playwright-cli` checks across `chrome`, `firefox`, and `webkit`, plus a mobile viewport flow in each engine when responsiveness or touch behavior changed.
+
 ### Yarn Install Hook
 
 ```bash

docs/agent-playbooks/skills-and-tools.md

@@ -39,6 +39,14 @@ Default to a fresh isolated browser session for normal verification. If the task
 
 Do not attach to a live personal browser session without explicit confirmation.
 
+When using `playwright-cli` for repo UI verification, run the relevant flow in all three main browser engines:
+
+- `chrome` for Blink
+- `firefox` for Gecko
+- `webkit` for Safari/WebKit coverage
+
+Use separate named sessions per engine so results stay isolated. If an engine is intentionally skipped, record why.
+
 ```bash
 npm install -g @playwright/cli@latest
 playwright-cli install --skills