Refine responsive Control UI chat controls

Summary:
- Add agent-scoped Control chat session filtering and agent-first session controls.
- Refine responsive chat controls, transcript, result-panel, and duplicate-message behavior.
- Reduce chat load churn by avoiding duplicate initial avatar refreshes.

Verification:
- pnpm test ui/src/ui/app-gateway.node.test.ts ui/src/ui/app-gateway-chat-load.node.test.ts ui/src/ui/chat/chat-responsive.browser.test.ts ui/src/ui/app-render.helpers.browser.test.ts ui/src/ui/app-render.helpers.node.test.ts ui/src/ui/views/chat.test.ts ui/src/ui/app-scroll.test.ts
- pnpm test src/plugin-sdk/file-lock.test.ts
- pnpm exec oxfmt --check --threads=1 ui/src/ui/chat/chat-responsive.browser.test.ts src/plugin-sdk/file-lock.test.ts
- pnpm --dir ui build
- Testbox pnpm check:changed: https://github.com/openclaw/openclaw/actions/runs/25309629891
- PR CI on cd22d3d1ab: https://github.com/openclaw/openclaw/actions/runs/25310534399

docs/web/control-ui.md

@@ -158,6 +158,9 @@ Imported themes are stored only in the current browser profile. They are not wri
     - During an active send and the final history refresh, the chat view keeps local optimistic user/assistant messages visible if `chat.history` briefly returns an older snapshot; the canonical transcript replaces those local messages once the Gateway history catches up.
     - Live `chat` events are delivery state, while `chat.history` is rebuilt from the durable session transcript. After tool-final events the Control UI reloads history and merges only a small optimistic tail; the transcript boundary is documented in [WebChat](/web/webchat).
     - `chat.inject` appends an assistant note to the session transcript and broadcasts a `chat` event for UI-only updates (no agent run, no channel delivery).
+    - The chat header shows the agent filter before the session picker, and the session picker is scoped by the selected agent. Switching agents shows only sessions tied to that agent and falls back to that agent's main session when it has no saved dashboard sessions yet.
+    - On desktop widths, chat controls stay on one compact row and collapse while scrolling down the transcript; scrolling up, returning to the top, or reaching the bottom restores the controls.
+    - Consecutive duplicate text-only messages render as one bubble with a count badge. Messages that carry images, attachments, tool output, or canvas previews are left uncollapsed.
     - The chat header model and thinking pickers patch the active session immediately through `sessions.patch`; they are persistent session overrides, not one-turn-only send options.
     - Typing `/new` in the Control UI creates and switches to the same fresh dashboard session as New Chat. Typing `/reset` keeps the Gateway's explicit in-place reset for the current session.
     - The chat model picker requests the Gateway's configured model view. If `agents.defaults.models` is present, that allowlist drives the picker. Otherwise the picker shows explicit `models.providers.*.models` entries plus providers with usable auth. The full catalog stays available through the debug `models.list` RPC with `view: "all"`.