feat(tui): animated working indicator with phase detection

- Braille spinner driven by a per-frame counter, shown in both the status
  bar (bottom) and at the bottom of the message area while a job runs
- phase detection (RunState::working_phase): running tool > thinking >
  streaming > generic, so the hint reads e.g. "⠹ shell: cargo test…"
- testable via the injected clock (tests/state_tests.rs)

crates/focus-tui/src/app.rs

@@ -208,6 +208,9 @@ pub struct App {
     /// 消息区视图高度（由 draw 填充）。
     /// Messages-area view height (filled by draw).
     pub view_height: u16,
+    /// 帧计数（供 spinner 动画）。
+    /// Frame counter (drives the spinner animation).
+    pub frame: u64,
     pub quit: bool,
 }
 
@@ -238,6 +241,7 @@ impl App {
             last_usage: None,
             geometry: Vec::new(),
             view_height: 0,
+            frame: 0,
             quit: false,
         }
     }
@@ -334,7 +338,7 @@ impl App {
         self.input.clear();
         self.caret = 0;
         self.follow = true;
-        self.status = "▶ running…".into();
+        self.status.clear(); // 动画 spinner 指示运行中 / the animated spinner shows "working"
         self.spawn_job(Some(text.to_string()));
     }
 

crates/focus-tui/src/state.rs

@@ -293,6 +293,34 @@ impl RunState {
         }
     }
 
+    /// 当前工作阶段（供 working 指示）：运行中的工具 / 思考中 / 流式输出。
+    /// The current working phase (for the working indicator): a running tool /
+    /// thinking / streaming.
+    pub fn working_phase(&self) -> String {
+        if let Some(exec) = self
+            .tool_execs
+            .iter()
+            .rev()
+            .find(|e| e.status == ExecStatus::Running)
+        {
+            return format!("{}…", exec.summary);
+        }
+        if let Some(p) = &self.partial {
+            // 以最后一个内容块为准：思考未结束 → thinking，否则视为流式输出。
+            // Look at the last content block: still thinking → "thinking…",
+            // otherwise treat it as streaming.
+            if p.content
+                .last()
+                .map(|c| matches!(c, ContentBlock::Thinking(_)))
+                .unwrap_or(false)
+            {
+                return "thinking…".to_string();
+            }
+            return "streaming…".to_string();
+        }
+        "working…".to_string()
+    }
+
     /// 消息结束时收尾未结算的思考计时。
     /// Finalize unsettled thinking timings at message end.
     pub fn finalize(&mut self) {

crates/focus-tui/src/ui.rs

@@ -56,6 +56,9 @@ pub fn run() -> io::Result<()> {
 /// Main loop: draw → handle input → drain background events.
 fn app_loop(terminal: &mut Terminal<CrosstermBackend<Stdout>>, app: &mut App) -> io::Result<()> {
     loop {
+        // 帧计数推进 spinner 动画。
+        // Advance the frame counter for the spinner animation.
+        app.frame = app.frame.wrapping_add(1);
         terminal.draw(|f| draw(f, app))?;
         if app.quit {
             return Ok(());
@@ -104,6 +107,25 @@ fn input_box_height(input: &str, width: u16) -> u16 {
     (rows.min(4) + 2) as u16
 }
 
+/// 动画 spinner 字符集（Braille）。
+/// The animated spinner character set (Braille).
+const SPINNER: [char; 10] = ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'];
+
+/// 按帧取 spinner 字符。
+/// Pick the spinner char for a frame.
+fn spinner(frame: u64) -> char {
+    SPINNER[(frame as usize) % SPINNER.len()]
+}
+
+/// 当前工作阶段：委托给运行状态的阶段检测。
+/// The current working phase: delegated to the run state.
+fn working_phase(app: &App) -> String {
+    match &app.run_state {
+        Some(rs) => rs.working_phase(),
+        None => "working…".to_string(),
+    }
+}
+
 /// 消息区：notes + 块列表 → 带几何的单 Paragraph。
 /// Messages area: notes + block list → one Paragraph with geometry.
 fn draw_messages(frame: &mut Frame, area: Rect, app: &mut App) {
@@ -120,10 +142,24 @@ fn draw_messages(frame: &mut Frame, area: Rect, app: &mut App) {
     ));
 
     let width = area.width.saturating_sub(1).max(1) as usize;
-    let (lines, geometry) = layout_blocks(&blocks, width);
+    let (mut lines, geometry) = layout_blocks(&blocks, width);
     app.geometry = geometry;
     app.view_height = area.height;
 
+    // 运行中：在消息区底部追加一行醒目的 working 指示。
+    // Running: append a prominent working line at the bottom of the messages.
+    if app.is_running() {
+        let phase = if !app.status.is_empty() {
+            app.status.clone()
+        } else {
+            working_phase(app)
+        };
+        lines.push(Line::from(Span::styled(
+            format!("{} {}", spinner(app.frame), phase),
+            Style::new().fg(Color::Yellow).bold(),
+        )));
+    }
+
     let total = lines.len() as u16;
     let max_scroll = total.saturating_sub(area.height.max(1));
     if app.follow {
@@ -412,10 +448,16 @@ fn draw_status(frame: &mut Frame, area: Rect, app: &App) {
         ratio,
         usage
     );
-    let right = if !app.status.is_empty() {
+    let right = if app.is_running() {
+        // 运行中：spinner + 阶段（或状态说明，如 "compacting…"）。
+        // Running: spinner + phase (or a status note like "compacting…").
+        if !app.status.is_empty() {
+            format!("{} {}", spinner(app.frame), app.status)
+        } else {
+            format!("{} {}", spinner(app.frame), working_phase(app))
+        }
+    } else if !app.status.is_empty() {
         app.status.clone()
-    } else if app.is_running() {
-        "▶ running…".to_string()
     } else {
         "Esc 退出 · Ctrl+D 继续 · Tab/点击 展开".to_string()
     };
@@ -423,10 +465,15 @@ fn draw_status(frame: &mut Frame, area: Rect, app: &App) {
     let width = area.width.saturating_sub(1) as usize;
     let left = truncate(&left, width.saturating_sub(20).max(10));
     let right = truncate(&right, 20);
+    let right_style = if app.is_running() {
+        Style::new().fg(Color::Yellow).bold()
+    } else {
+        Style::new().fg(Color::DarkGray)
+    };
     let line = Line::from(vec![
         Span::styled(left, Style::new().fg(Color::Blue).bold()),
         Span::styled("  ", dim_style()),
-        Span::styled(right, Style::new().fg(Color::DarkGray)),
+        Span::styled(right, right_style),
     ]);
     frame.render_widget(Paragraph::new(line).alignment(Alignment::Left), area);
 }

crates/focus-tui/tests/state_tests.rs

@@ -229,3 +229,53 @@ fn build_blocks_includes_live_run() {
     // A later block appeared → the duration is settled.
     assert_eq!(thinking.1, Some(250));
 }
+
+/// working 阶段检测：运行中的工具 > 思考中 > 流式输出。
+/// Working-phase detection: running tool > thinking > streaming.
+#[test]
+fn working_phase_detection() {
+    let fc = FakeClock::new();
+    let mut rs = RunState::new(fc.clock());
+    // 无状态 → 一般工作。
+    // No state → generic work.
+    assert_eq!(rs.working_phase(), "working…");
+
+    // 思考中。
+    // Thinking.
+    rs.on_agent_event(&AgentEvent::MessageStart {
+        message: Message::Assistant(assistant(vec![thinking_block("hmm")])),
+    });
+    assert_eq!(rs.working_phase(), "thinking…");
+
+    // 流式输出（思考后出现文本）。
+    // Streaming (text after thinking).
+    rs.on_agent_event(&AgentEvent::MessageUpdate {
+        message: Message::Assistant(assistant(vec![
+            thinking_block("hmm"),
+            ContentBlock::text("answer"),
+        ])),
+        event_type: "text_start".into(),
+    });
+    assert_eq!(rs.working_phase(), "streaming…");
+
+    // 运行中的工具优先。
+    // A running tool takes precedence.
+    let mut args = JsonValue::obj();
+    args.insert("command", "cargo test".into()).ok();
+    rs.on_agent_event(&AgentEvent::ToolExecutionStart {
+        tool_call_id: "c1".into(),
+        tool_name: "shell".into(),
+        args,
+    });
+    assert_eq!(rs.working_phase(), "shell: cargo test…");
+
+    // 工具结束后回到流式。
+    // Back to streaming after the tool finishes.
+    rs.on_agent_event(&AgentEvent::ToolExecutionEnd {
+        tool_call_id: "c1".into(),
+        tool_name: "shell".into(),
+        result: ToolResult::text("ok"),
+        is_error: false,
+    });
+    assert_eq!(rs.working_phase(), "streaming…");
+}