fix(tui): show live submit disposition in composer hint (#345)

When the user has typed something into the composer and hits Enter, the
message goes to one of four fates depending on engine state:

- Immediate (idle + online) — most common, sends right away
- Steer (busy + tool execution) — forwards mid-turn
- QueueFollowUp (busy + streaming text) — parks for after TurnComplete
- Queue (offline) — parks on offline queue

Previously the user had no way to tell which would fire BEFORE pressing
Enter. The disposition flips with fast-changing internal state (whether
the model is currently streaming text vs. running a tool, whether
network connectivity has just dropped) and only the post-submit status
toast hinted at the result — which is too late if you wanted a different
behaviour.

Fix: extend the composer's bottom hint line so when the composer has
non-empty content, it shows what Enter will do RIGHT NOW. The hint flips
live with engine state, so the user sees the real behaviour before
pressing Enter:

  ↵ steer into current turn        (sky blue, busy + tool execution)
  ↵ queue for next turn            (muted, busy + streaming)
  ↵ offline queue (no engine)      (warning yellow, offline)

The Immediate case stays unhinted — that's the default and surfacing it
would be noise.

Closes #345.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/tui/src/tui/widgets/mod.rs

@@ -362,14 +362,42 @@ impl Renderable for ComposerWidget<'_> {
                         Style::default().fg(palette::TEXT_MUTED),
                     ),
                 ]))
-            } else if self.slash_menu_entries.is_empty() {
-                None
-            } else {
+            } else if !self.slash_menu_entries.is_empty() {
                 Some(Line::from(vec![
                     Span::styled(" Up/Down move  ", Style::default().fg(palette::TEXT_MUTED)),
                     Span::styled("Tab accept  ", Style::default().fg(palette::TEXT_MUTED)),
                     Span::styled("Esc close", Style::default().fg(palette::TEXT_MUTED)),
                 ]))
+            } else if !input_text.trim().is_empty() {
+                // Live disambiguation for #345: when there's content in the
+                // composer, show what `Enter` will do RIGHT NOW so the user
+                // never has to guess between Immediate / Steer / QueueFollowUp /
+                // Queue. The disposition flips with engine state so this hint
+                // is the only reliable cue before pressing Enter.
+                use crate::tui::app::SubmitDisposition;
+                let (label, color) = match self.app.decide_submit_disposition() {
+                    SubmitDisposition::Immediate => (None, palette::TEXT_MUTED),
+                    SubmitDisposition::Steer => (
+                        Some("↵ steer into current turn"),
+                        palette::DEEPSEEK_SKY,
+                    ),
+                    SubmitDisposition::QueueFollowUp => (
+                        Some("↵ queue for next turn"),
+                        palette::TEXT_MUTED,
+                    ),
+                    SubmitDisposition::Queue => (
+                        Some("↵ offline queue (no engine)"),
+                        palette::STATUS_WARNING,
+                    ),
+                };
+                label.map(|text| {
+                    Line::from(vec![Span::styled(
+                        format!(" {text} "),
+                        Style::default().fg(color),
+                    )])
+                })
+            } else {
+                None
             };
 
             let mut block = Block::default()