[建议 / Feature] Sticky latest prompt (Grok Build-style), inline image/video/audio previews in chat, git branch switcher

提交前确认 · Pre-submission checklist

• I searched existing issues and confirmed this isn't a duplicate.
• I've read CONTRIBUTING.md.

问题类别 · Category

UI / 界面体验 · UI / UX

涉及的 Agent 框架 · Agent framework

ZCode Agent（自研）

使用场景 · Use case

Three related UX gaps I hit daily in long agentic sessions (CLI on macOS):

1. The original prompt disappears during long runs. When an agent run spans 20+ tool calls, file edits and test output, the user prompt scrolls out of view almost immediately. To re-check what was actually asked — especially after context compaction in long sessions — I have to scroll all the way up or search the transcript.

2. Media files show up as bare paths. When images, videos or audio appear in a session — pasted attachments, screenshots from browser/device tools, or files the agent generates — the chat shows only a file path or filename. I have to leave the chat (Finder / open) to see what was attached or what the agent just produced.

3. Branch switching requires a terminal. A session is deeply tied to repo state, but switching branches means leaving ZCode for a terminal and typing git checkout. Doing that mid-run also silently changes the working tree the agent is editing, with no guard.

建议方案 · Proposal

1. Sticky "latest prompt" at the top of chat (like Grok Build). Pin the most recent user prompt as a compact sticky bar at the top of the chat panel: first line as summary, expand-on-click for the full text. It updates automatically on each new prompt and survives context compaction. Optional: "edit & resend" affordance on the pinned prompt.

2. Inline media previews in chat.

• Image: inline thumbnail in the message bubble, click for full-size lightbox.
• Video: first-frame thumbnail with play button, playback in an overlay (or inline player).
• Audio: inline player with duration and a scrub/waveform bar — relevant for voice notes and TTS output.

3. Git branch switcher. A branch indicator + switcher in the status line / command palette: list local (and remote-tracking) branches, one-action checkout, and a confirmation when there are uncommitted changes or a running task, so the agent never gets its working tree swapped mid-edit.

预期价值 · Expected value

1. Removes scroll-hunting in every long task — the goal stays visible while the agent works; also helps verify the agent is still on-task after compaction.
2. Closes the loop between "agent produced media" and "user can verify it" without leaving chat — critical for UI/design work, screenshot verification and generated assets.
3. Fewer context switches, plus a safety guard against the classic "checkout underneath a running agent" conflict.

你认为的优先级 · Your perceived priority

中 · Medium

你使用的 ZCode 版本 / 环境 · ZCode version / environment

ZCode CLI v0.16.5, macOS 15 (Apple Silicon)

补充材料 · Additional context

• For #3: #132 (worktree switcher — same UX surface, different primitive; a branch switcher complements it) and #220 (native /worktree command).
• Reference for #1: Grok Build keeps the last sent prompt pinned above the working output.
• All three are small independently shippable features; #1 and #2 share the chat renderer surface.

Treat this as three separate proposals: sticky latest prompt and media previews in the chat panel, plus branch switching in the status line or command palette. Read related issues #132 and #220 first, then define separate acceptance checks for prompt persistence, image/video/audio previews, and guarded branch checkout. Done means each interaction works in ZCode and respects running-task or uncommitted-change warnings.