chore(skill): document why each git-log path is watched

Replace the stale reference to the upstream "client side changes" workflow
with an inline explanation of what each watched path can affect on the
Java side, so the rolling instructions stand on their own.

Author: yury-s

.claude/skills/playwright-roll/SKILL.md

@@ -11,9 +11,13 @@ Afterwards, walk through the upstream changes that affect the Java client and po
 
 ## Determining what to port
 
-Don't rely on the "Backport client side changes" issue (microsoft/playwright-java#xxxx). The workflow that maintains it is being phased out and the issue is incomplete/stale.
+List the upstream commits that touched a client-relevant path since the last release. The paths cover everything that can change the public Java surface or the wire protocol:
 
-Instead, list the upstream commits that touched a client-relevant path since the last release. The triggering paths come from `~/playwright/.github/workflows/pr_check_client_side_changes.yml`:
+- `docs/src/api/` — the source of truth for `api.json`. Method/option additions, removals, and `langs:` filter changes flow from here.
+- `packages/playwright-core/src/client/` — the JS client implementation that the Java client mirrors.
+- `packages/isomorphic/` — selector engines, locator generation/parsing, and aria-snapshot logic shared between client and server. Changes here can affect client-side helpers like `getByRoleSelector`.
+- `packages/playwright/src/matchers/matchers.ts` — assertion-method definitions. Changes here usually correspond to new options on `LocatorAssertions` / `PageAssertions`.
+- `packages/protocol/src/protocol.yml` — the wire protocol schema. Method/event additions, parameter renames, and result-shape changes affect what the Java `*Impl` classes need to send/receive.
 
 ```bash
 cd ~/playwright