docs(contributing): require before/after screenshots for UI PRs (#32206)

Merged via squash.

Prepared head SHA: d7f0914873
Co-authored-by: hydro13 <6640526+hydro13@users.noreply.github.com>
Co-authored-by: altaywtf <9790196+altaywtf@users.noreply.github.com>
Reviewed-by: @altaywtf

CHANGELOG.md

@@ -391,6 +391,10 @@ Docs: https://docs.openclaw.ai
 
 ## Unreleased
 
+### Changes
+
+- Docs/Contributing: require before/after screenshots for UI or visual PRs in the pre-PR checklist. (#32206) Thanks @hydro13.
+
 ### Fixes
 
 - Feishu/Multi-account + reply reliability: add `channels.feishu.defaultAccount` outbound routing support with schema validation, prevent inbound preview text from leaking into prompt system events, keep quoted-message extraction text-first (post/interactive/file placeholders instead of raw JSON), route Feishu video sends as `msg_type: "file"`, and avoid websocket event blocking by using non-blocking event handling in monitor dispatch. Landed from contributor PRs #31209, #29610, #30432, #30331, and #29501. Thanks @stakeswky, @hclsys, @bmendonca3, @patrick-yingxi-pan, and @zwffff.

CONTRIBUTING.md

@@ -74,6 +74,7 @@ Welcome to the lobster tank! 🦞
 - Ensure CI checks pass
 - Keep PRs focused (one thing per PR; do not mix unrelated concerns)
 - Describe what & why
+- **Include screenshots** — one showing the problem/before, one showing the fix/after (for UI or visual changes)
 
 ## Control UI Decorators