fix(fleet-watcher): reflow on terminal resize

openspec/changes/agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-05-15

openspec/changes/agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11/proposal.md

@@ -0,0 +1,18 @@
+## Why
+
+`fleet-watcher` rendered narrower than the actual terminal width and didn't reflow when the tmux pane / kitty window was resized. Root cause: `WatcherView` only subscribed to `EventClause::Tick`. When the terminal emitted a `WindowResize` event, the catch-all `_ => None` arm in `on()` swallowed it, so no `Msg` was returned, `Model::update` never set `redraw = true`, and the dashboard waited up to 2 seconds for the next Tick (or stayed at the cached layout indefinitely if the Tick happened to coincide with a no-op draw).
+
+## What Changes
+
+- `Msg::Resize` variant added so resize events can be dispatched into the existing update loop without overloading the `Tick` semantics.
+- `WatcherView::on()` matches `Event::WindowResize(_, _)` and returns `Some(Msg::Resize)`.
+- `WatcherView` subscription list now includes `Sub::new(EventClause::WindowResize, SubClause::Always)` alongside the existing `Tick` subscription so tuirealm actually routes resize events to the component.
+- `Model::update()` handles `Msg::Resize` symmetrically with `Msg::Tick` — sets `redraw = true` (already unconditional at the top of the match) without further state changes. ratatui's `Terminal::draw` autoresizes the back buffer on the next call, so the dashboard immediately reflows to fill the new surface.
+- Regression test `window_resize_event_triggers_redraw_message` exercises the resize path directly through `WatcherView::on()` and asserts a non-`None` `Msg` is returned.
+
+## Impact
+
+- Affected surface: `rust/fleet-watcher/src/main.rs` only. Other fleet TUIs (`fleet-state`, `fleet-waves`, `fleet-plan-tree`, `fleet-tui-poc`) share the same Tick-only subscription pattern and likely have the same bug, but they're out of scope for this PR. The user opted to fix watcher first; a follow-up can mirror the pattern across the family.
+- Risk: very low. Adding a Msg variant and a subscription is additive. Existing `Msg::Tick`/`Msg::Quit` behavior is unchanged, all 6 pre-existing tests stay green, and the snapshot rendering is unaffected (it doesn't go through the event loop).
+- Rollout: ship with the next `cargo build --release` of `fleet-watcher`. No config flag. Operators don't need to do anything; the watcher will start reflowing on resize automatically.
+- No version bump or release-note edit required (internal binary, no published artifact).

openspec/changes/agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11/specs/fleet-watcher-resize-redraw/spec.md

@@ -0,0 +1,17 @@
+## ADDED Requirements
+
+### Requirement: fleet-watcher MUST reflow on terminal resize
+`fleet-watcher` SHALL trigger a redraw within one event-loop iteration when the terminal or hosting tmux pane reports a `WindowResize` event, so the dashboard immediately uses the full new width/height instead of waiting for the next periodic tick.
+
+#### Scenario: WindowResize event produces a redraw-triggering Msg
+- **GIVEN** a `WatcherView` mounted in the tuirealm `Application` with both `EventClause::Tick` and `EventClause::WindowResize` subscriptions active
+- **WHEN** the terminal backend emits `Event::WindowResize(width, height)` (e.g. tmux pane grew, kitty window resized, or `SIGWINCH` after a layout change)
+- **THEN** `WatcherView::on()` SHALL return `Some(Msg::Resize)` (not `None`)
+- **AND** `Model::update(Msg::Resize)` SHALL set `redraw = true`
+- **AND** the next `Model::view()` SHALL render at the new `frame.area()` so headers, stat cards, the review queue, and the diff sparkline span the full width
+
+#### Scenario: Existing Tick and Quit paths are unaffected
+- **GIVEN** the same mounted `WatcherView`
+- **WHEN** `Event::Tick` fires every 2 seconds
+- **THEN** `Msg::Tick` SHALL still be returned and the tick counter SHALL advance
+- **AND** keyboard `q` / `Esc` SHALL still produce `Msg::Quit` and terminate the app on the next loop iteration

openspec/changes/agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11/tasks.md

@@ -0,0 +1,34 @@
+## Definition of Done
+
+This change is complete only when **all** of the following are true:
+
+- Every checkbox below is checked.
+- The agent branch reaches `MERGED` state on `origin` and the PR URL + state are recorded in the completion handoff.
+- If any step blocks (test failure, conflict, ambiguous result), append a `BLOCKED:` line under section 4 explaining the blocker and **STOP**. Do not tick remaining cleanup boxes; do not silently skip the cleanup pipeline.
+
+## Handoff
+
+- Handoff: change=`agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11`; branch=`agent/<your-name>/<branch-slug>`; scope=`TODO`; action=`continue this sandbox or finish cleanup after a usage-limit/manual takeover`.
+- Copy prompt: Continue `agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11` on branch `agent/<your-name>/<branch-slug>`. Work inside the existing sandbox, review `openspec/changes/agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11/tasks.md`, continue from the current state instead of creating a new sandbox, and when the work is done run `gx branch finish --branch agent/<your-name>/<branch-slug> --base dev --via-pr --wait-for-merge --cleanup`.
+
+## 1. Specification
+
+- [x] 1.1 Finalize proposal scope and acceptance criteria for `agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11`.
+- [x] 1.2 Define normative requirements in `specs/fleet-watcher-resize-redraw/spec.md`.
+
+## 2. Implementation
+
+- [x] 2.1 Implement scoped behavior changes — added `Msg::Resize` variant, `WindowResize` arm in `WatcherView::on()`, `WindowResize` subscription in `Model::init_app()`, and `Msg::Resize` handling in `Model::update()`. All within `rust/fleet-watcher/src/main.rs`.
+- [x] 2.2 Add/update focused regression coverage — new test `window_resize_event_triggers_redraw_message` calls `WatcherView::on(&Event::WindowResize(200, 60))` and asserts the returned `Msg` is `Some(_)`. Verified failure before fix, then green after.
+
+## 3. Verification
+
+- [x] 3.1 Run targeted project verification commands — `cargo test -p fleet-watcher` from `rust/` → 7 passed, 0 failed (1 new + 6 pre-existing).
+- [x] 3.2 Run `openspec validate agent-claude-fleet-watcher-resize-redraw-2026-05-16-01-11 --type change --strict` — "Change ... is valid".
+- [x] 3.3 Run `openspec validate --specs` — no main-spec deltas in this change; the requirement lives only on the change's delta spec.
+
+## 4. Cleanup (mandatory; run before claiming completion)
+
+- [ ] 4.1 Run the cleanup pipeline: `gx branch finish --branch agent/<your-name>/<branch-slug> --base dev --via-pr --wait-for-merge --cleanup`. This handles commit -> push -> PR create -> merge wait -> worktree prune in one invocation.
+- [ ] 4.2 Record the PR URL and final merge state (`MERGED`) in the completion handoff.
+- [ ] 4.3 Confirm the sandbox worktree is gone (`git worktree list` no longer shows the agent path; `git branch -a` shows no surviving local/remote refs for the branch).

rust/fleet-watcher/src/main.rs

@@ -33,6 +33,7 @@ use tuirealm::terminal::{CrosstermTerminalAdapter, TerminalAdapter};
 pub enum Msg {
     Tick,
     Quit,
+    Resize,
 }
 
 #[derive(Debug, Eq, PartialEq, Clone, Hash)]
@@ -1074,6 +1075,12 @@ impl<F: PrFeed + 'static> AppComponent<Msg, NoUserEvent> for WatcherView<F> {
                 self.tick = self.tick.wrapping_add(1);
                 Some(Msg::Tick)
             }
+            // Terminal/tmux pane resized — emit a Msg so the Model loop sets
+            // redraw=true on the same iteration instead of waiting up to 2s
+            // for the next Tick. ratatui's `Terminal::draw` autoresizes the
+            // back buffer, so the next draw immediately picks up the new
+            // width/height and the dashboard reflows to fill the surface.
+            Event::WindowResize(_, _) => Some(Msg::Resize),
             _ => None,
         }
     }
@@ -1108,7 +1115,10 @@ impl Model<CrosstermTerminalAdapter> {
         app.mount(
             Id::Watcher,
             Box::new(WatcherView::default()),
-            vec![Sub::new(EventClause::Tick, SubClause::Always)],
+            vec![
+                Sub::new(EventClause::Tick, SubClause::Always),
+                Sub::new(EventClause::WindowResize, SubClause::Always),
+            ],
         )?;
         app.active(&Id::Watcher)?;
         Ok(app)
@@ -1134,7 +1144,7 @@ impl<T: TerminalAdapter> Model<T> {
         self.redraw = true;
         match msg {
             Msg::Quit => self.quit = true,
-            Msg::Tick => {}
+            Msg::Tick | Msg::Resize => {}
         }
     }
 }
@@ -1293,6 +1303,21 @@ mod tests {
         assert!(frame.contains("no merged diff activity yet"));
     }
 
+    #[test]
+    fn window_resize_event_triggers_redraw_message() {
+        // Regression for the "not full width / not dynamic" complaint:
+        // WatcherView only subscribed to Tick events, so terminal resize
+        // events (Event::WindowResize) were swallowed by the catch-all
+        // `_ => None` arm. The model never set `redraw = true` and the
+        // dashboard stayed at its previous layout until the next 2s tick.
+        let mut view = WatcherView::with_feed(StubPrFeed::fixture());
+        let msg = view.on(&Event::WindowResize(200, 60));
+        assert!(
+            msg.is_some(),
+            "WindowResize must produce a Msg so Model::update sets redraw=true"
+        );
+    }
+
     #[test]
     fn render_sixty_row_snapshot_for_pr_body() {
         let mut view = WatcherView::with_feed(StubPrFeed::fixture());