feat: complete Phase 12 — voice playback ticker, cache, config, and UI

Add playback position ticker in event loop with 1s UI refresh rate,
integrate VoiceCache for downloaded voice files, add [audio] config
section (cache_size_mb, auto_download_voice), and render progress bar
with waveform visualization in message bubbles.

Fix race conditions in AudioPlayer: add `starting` flag to prevent
false `is_stopped()` during ffplay startup, guard pid cleanup so old
threads don't overwrite newer process pids. Implement `resume_from()`
with ffplay `-ss` for real audio seek on unpause (-1s rewind).

Kill ffplay on app exit via `stop_playback()` in shutdown + Drop impl.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/ui/components/message_bubble.rs

@@ -7,7 +7,7 @@
 
 use crate::config::Config;
 use crate::formatting;
-use crate::tdlib::MessageInfo;
+use crate::tdlib::{MessageInfo, PlaybackState, PlaybackStatus};
 #[cfg(feature = "images")]
 use crate::tdlib::PhotoDownloadState;
 use crate::types::MessageId;
@@ -200,6 +200,7 @@ pub fn render_message_bubble(
     config: &Config,
     content_width: usize,
     selected_msg_id: Option<MessageId>,
+    playback_state: Option<&PlaybackState>,
 ) -> Vec<Line<'static>> {
     let mut lines = Vec::new();
     let is_selected = selected_msg_id == Some(msg.id());
@@ -394,6 +395,47 @@ pub fn render_message_bubble(
         }
     }
 
+    // Отображаем индикатор воспроизведения голосового
+    if msg.has_voice() {
+        if let Some(voice) = msg.voice_info() {
+            let is_this_playing = playback_state
+                .map(|ps| ps.message_id == msg.id())
+                .unwrap_or(false);
+
+            let status_line = if is_this_playing {
+                let ps = playback_state.unwrap();
+                let icon = match ps.status {
+                    PlaybackStatus::Playing => "▶",
+                    PlaybackStatus::Paused => "⏸",
+                    PlaybackStatus::Loading => "⏳",
+                    _ => "⏹",
+                };
+                let bar = render_progress_bar(ps.position, ps.duration, 20);
+                format!(
+                    "{} {} {:.0}s/{:.0}s",
+                    icon, bar, ps.position, ps.duration
+                )
+            } else {
+                let waveform = render_waveform(&voice.waveform, 20);
+                format!("  {} {:.0}s", waveform, voice.duration)
+            };
+
+            let status_len = status_line.chars().count();
+            if msg.is_outgoing() {
+                let padding = content_width.saturating_sub(status_len + 1);
+                lines.push(Line::from(vec![
+                    Span::raw(" ".repeat(padding)),
+                    Span::styled(status_line, Style::default().fg(Color::Cyan)),
+                ]));
+            } else {
+                lines.push(Line::from(Span::styled(
+                    status_line,
+                    Style::default().fg(Color::Cyan),
+                )));
+            }
+        }
+    }
+
     // Отображаем статус фото (если есть)
     #[cfg(feature = "images")]
     if let Some(photo) = msg.photo_info() {
@@ -469,3 +511,43 @@ pub fn calculate_image_height(img_width: i32, img_height: i32, content_width: us
     let raw_height = (display_width as f64 * aspect * 0.5) as u16;
     raw_height.clamp(MIN_IMAGE_HEIGHT, MAX_IMAGE_HEIGHT)
 }
+
+/// Рендерит progress bar для воспроизведения
+fn render_progress_bar(position: f32, duration: f32, width: usize) -> String {
+    if duration <= 0.0 {
+        return "─".repeat(width);
+    }
+    let ratio = (position / duration).clamp(0.0, 1.0);
+    let filled = (ratio * width as f32) as usize;
+    let empty = width.saturating_sub(filled + 1);
+    format!("{}●{}", "━".repeat(filled), "─".repeat(empty))
+}
+
+/// Рендерит waveform из base64-encoded данных TDLib
+fn render_waveform(waveform_b64: &str, width: usize) -> String {
+    const BARS: &[char] = &['▁', '▂', '▃', '▄', '▅', '▆', '▇', '█'];
+
+    if waveform_b64.is_empty() {
+        return "▁".repeat(width);
+    }
+
+    // Декодируем waveform (каждый байт = амплитуда 0-255)
+    use base64::Engine;
+    let bytes = base64::engine::general_purpose::STANDARD
+        .decode(waveform_b64)
+        .unwrap_or_default();
+
+    if bytes.is_empty() {
+        return "▁".repeat(width);
+    }
+
+    // Сэмплируем до нужной ширины
+    let mut result = String::with_capacity(width * 4);
+    for i in 0..width {
+        let byte_idx = i * bytes.len() / width;
+        let amplitude = bytes.get(byte_idx).copied().unwrap_or(0);
+        let bar_idx = (amplitude as usize * (BARS.len() - 1)) / 255;
+        result.push(BARS[bar_idx]);
+    }
+    result
+}

src/ui/messages.rs

@@ -234,6 +234,7 @@ fn render_message_list<T: TdClientTrait>(f: &mut Frame, area: Rect, app: &mut Ap
                     app.config(),
                     content_width,
                     selected_msg_id,
+                    app.playback_state.as_ref(),
                 );
 
                 // Собираем deferred image renders для всех загруженных фото