feat: implement Phase 11 — inline photo viewing with ratatui-image

Add feature-gated (`images`) inline photo support:
- New types: MediaInfo, PhotoInfo, PhotoDownloadState, ImagesConfig
- Media module: ImageCache (LRU filesystem cache), ImageRenderer (terminal protocol detection)
- Photo metadata extraction from TDLib MessagePhoto with download_file() API
- ViewImage command (v/м) to toggle photo expand/collapse in message selection
- Two-pass UI rendering: placeholder lines in message bubbles + StatefulImage overlay
- Collapse all expanded photos on Esc (exit selection mode)

Dependencies: ratatui-image 8.1, image 0.25 (optional, behind `images` feature flag)

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

src/app/mod.rs

@@ -85,6 +85,11 @@ pub struct App<T: TdClientTrait = TdClient> {
     // Typing indicator
     /// Время последней отправки typing status (для throttling)
     pub last_typing_sent: Option<std::time::Instant>,
+    // Image support
+    #[cfg(feature = "images")]
+    pub image_renderer: Option<crate::media::image_renderer::ImageRenderer>,
+    #[cfg(feature = "images")]
+    pub image_cache: Option<crate::media::cache::ImageCache>,
 }
 
 impl<T: TdClientTrait> App<T> {
@@ -104,6 +109,13 @@ impl<T: TdClientTrait> App<T> {
         let mut state = ListState::default();
         state.select(Some(0));
 
+        #[cfg(feature = "images")]
+        let image_cache = Some(crate::media::cache::ImageCache::new(
+            config.images.cache_size_mb,
+        ));
+        #[cfg(feature = "images")]
+        let image_renderer = crate::media::image_renderer::ImageRenderer::new();
+
         App {
             config,
             screen: AppScreen::Loading,
@@ -126,6 +138,10 @@ impl<T: TdClientTrait> App<T> {
             search_query: String::new(),
             needs_redraw: true,
             last_typing_sent: None,
+            #[cfg(feature = "images")]
+            image_renderer,
+            #[cfg(feature = "images")]
+            image_cache,
         }
     }