feat(viewer): WMV cutscene player with scrub, keyboard + audio

Add an in-explorer video player for the dat/movie/*.wmv cutscenes.

Decode via the ffmpeg/ffprobe CLI (no libav linking): video streams from an
`ffmpeg -f rawvideo -pix_fmt rgba` pipe read into fixed w*h*4 frame chunks over
a bounded channel (paused/behind => ffmpeg back-pressures on its pipe); one
reused Image is overwritten in place each tick. Audio is best-effort: the track
is pre-decoded to a temp stereo WAV and played through a rodio Sink (volume /
play / pause / seek-via-skip_duration for free). Native-only under
cfg(not(wasm32)); VideoPreview registers unconditionally so the UI compiles for
wasm. Mirrors the .pak load pipeline (FileSelected -> bg thread ->
IsoLoaderMsg::VideoLoaded -> apply_loaded_video -> advance_video_playback), with
a single free_video teardown wired into every other viewer's reset.

Controls:
- play/pause button, click-on-frame toggle, Space / arrow (+-10s) shortcuts
- seekable timeline with mm:ss labels; volume slider (greyed when no audio)
- live scrubbing: a coalescing one-shot `ffmpeg -ss -frames:v 1` grabber always
  jumps to the knob's latest position, so dragging shows the frame under the
  knob in real time; that grabbed frame also bridges the gap after a commit-seek
  so there's no black flash while the streaming decoder catches up.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/sylpheed-viewer/src/ui.rs

@@ -11,7 +11,7 @@ use bevy_egui::{egui, EguiContexts};
 
 use crate::iso_loader::{
     FileInfo, FileSelected, IsoState, PakView, RequestOpenDir, RequestOpenIso, SkyboxPreview,
-    TextPreview, TexturePreview, IsoLoaderSystemSet,
+    TextPreview, TexturePreview, VideoPreview, IsoLoaderSystemSet,
 };
 use crate::ViewerState;
 
@@ -132,6 +132,7 @@ fn draw_viewer_ui(
     text_preview: Res<TextPreview>,
     mut pak_view: ResMut<PakView>,
     skybox: Res<SkyboxPreview>,
+    mut video: ResMut<VideoPreview>,
     file_info: Res<FileInfo>,
     mut open_iso_events: EventWriter<RequestOpenIso>,
     mut open_dir_events: EventWriter<RequestOpenDir>,
@@ -266,6 +267,8 @@ fn draw_viewer_ui(
                         ui.label(format!("Loading {name}…"));
                     });
                 });
+            } else if video.active {
+                draw_video_player(ui, &mut video);
             } else if !skybox.faces.is_empty() {
                 draw_skybox_grid(ui, &skybox);
             } else if pak_view.loaded {
@@ -489,6 +492,120 @@ fn draw_pak_browser(ui: &mut egui::Ui, pak: &mut PakView) {
     }
 }
 
+// ── Video player (WMV cutscenes) ──────────────────────────────────────────────
+
+/// Format seconds as `mm:ss`.
+fn fmt_time(secs: f32) -> String {
+    let s = secs.max(0.0) as u32;
+    format!("{:02}:{:02}", s / 60, s % 60)
+}
+
+/// Central-panel video player: the current frame plus a transport bar
+/// (play/pause, seekable timeline, volume). Also supports click-to-toggle and
+/// keyboard shortcuts (space = play/pause, ←/→ = skip 10 s). Playback state
+/// lives in `VideoPreview`; the decode/audio engine reacts to it in
+/// `advance_video_playback`.
+fn draw_video_player(ui: &mut egui::Ui, video: &mut VideoPreview) {
+    // ── Keyboard shortcuts (consumed so focused widgets don't also act). ──
+    let (mut toggle_play, mut skip) = (false, 0.0_f32);
+    ui.input_mut(|i| {
+        if i.consume_key(egui::Modifiers::NONE, egui::Key::Space) {
+            toggle_play = true;
+        }
+        if i.consume_key(egui::Modifiers::NONE, egui::Key::ArrowRight) {
+            skip += 10.0;
+        }
+        if i.consume_key(egui::Modifiers::NONE, egui::Key::ArrowLeft) {
+            skip -= 10.0;
+        }
+    });
+    if toggle_play {
+        video.playing = !video.playing;
+    }
+    if skip != 0.0 {
+        let t = (video.position + skip).clamp(0.0, video.duration);
+        video.position = t;
+        video.scrub_request = Some(t); // instant preview via the grabber…
+        video.seek_request = Some(t); // …then the stream restarts here
+    }
+
+    ui.horizontal(|ui| {
+        ui.heading(&video.name);
+        ui.separator();
+        ui.label(format!("{}×{}  ·  wmv3 / wmapro", video.width, video.height));
+        if !video.has_audio {
+            ui.separator();
+            ui.colored_label(egui::Color32::YELLOW, "no audio");
+        }
+    });
+    ui.separator();
+
+    // Reserve room for the transport row so the frame never pushes it off-screen.
+    const CONTROLS_H: f32 = 34.0;
+    let avail = ui.available_size();
+    let frame_h = (avail.y - CONTROLS_H).max(0.0);
+    let (w, h) = (video.width.max(1) as f32, video.height.max(1) as f32);
+    let scale = (avail.x / w).min(frame_h / h);
+    let (disp_w, disp_h) = (w * scale, h * scale);
+
+    if let Some(egui_id) = video.egui_id {
+        ui.allocate_ui(egui::vec2(avail.x, frame_h), |ui| {
+            ui.vertical_centered(|ui| {
+                // Click the frame to toggle play/pause.
+                let resp = ui.add(
+                    egui::Image::new(egui::load::SizedTexture::new(egui_id, [disp_w, disp_h]))
+                        .sense(egui::Sense::click()),
+                );
+                if resp.clicked() {
+                    video.playing = !video.playing;
+                }
+            });
+        });
+    }
+
+    // ── Transport bar ──
+    ui.horizontal(|ui| {
+        if ui.button(if video.playing { "⏸" } else { "▶" }).clicked() {
+            video.playing = !video.playing;
+        }
+        ui.label(fmt_time(video.position));
+
+        // Timeline fills the space left after reserving room for the total-time
+        // label and the volume control on the right. Dragging scrubs live (the
+        // grabber shows the frame under the knob); release commits the seek.
+        let reserved = 170.0;
+        let tl_width = (ui.available_width() - reserved).max(80.0);
+        ui.spacing_mut().slider_width = tl_width;
+        let mut pos = video.position;
+        let resp =
+            ui.add(egui::Slider::new(&mut pos, 0.0..=video.duration.max(0.1)).show_value(false));
+        if resp.changed() {
+            video.position = pos; // knob + label follow immediately
+            video.scrub_request = Some(pos);
+            if resp.dragged() {
+                video.scrubbing = true;
+            } else {
+                // A click on the track (no drag) → commit right away.
+                video.seek_request = Some(pos);
+                video.scrubbing = false;
+            }
+        }
+        if resp.drag_stopped() {
+            video.seek_request = Some(pos);
+            video.scrubbing = false;
+        }
+        ui.label(fmt_time(video.duration));
+
+        ui.separator();
+        ui.label("🔊");
+        ui.spacing_mut().slider_width = 90.0;
+        ui.add_enabled(
+            video.has_audio,
+            egui::Slider::new(&mut video.volume, 0.0..=1.0).show_value(false),
+        );
+    });
+}
+
 // ── World cubemap (skybox) viewer ─────────────────────────────────────────────
 
 /// Show a world cubemap's 6 faces in a labelled grid (D3D9 order). A true