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>

tests/config.rs

@@ -1,6 +1,6 @@
 // Integration tests for config flow
 
-use tele_tui::config::{Config, ColorsConfig, GeneralConfig, Keybindings, NotificationsConfig};
+use tele_tui::config::{Config, ColorsConfig, GeneralConfig, ImagesConfig, Keybindings, NotificationsConfig};
 
 /// Test: Дефолтные значения конфигурации
 #[test]
@@ -34,6 +34,7 @@ fn test_config_custom_values() {
         },
         keybindings: Keybindings::default(),
         notifications: NotificationsConfig::default(),
+        images: ImagesConfig::default(),
     };
 
     assert_eq!(config.general.timezone, "+05:00");
@@ -118,6 +119,7 @@ fn test_config_toml_serialization() {
         },
         keybindings: Keybindings::default(),
         notifications: NotificationsConfig::default(),
+        images: ImagesConfig::default(),
     };
 
     // Сериализуем в TOML