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>

Cargo.toml

@@ -10,10 +10,11 @@ keywords = ["telegram", "tui", "terminal", "cli"]
 categories = ["command-line-utilities"]
 
 [features]
-default = ["clipboard", "url-open", "notifications"]
+default = ["clipboard", "url-open", "notifications", "images"]
 clipboard = ["dep:arboard"]
 url-open = ["dep:open"]
 notifications = ["dep:notify-rust"]
+images = ["dep:ratatui-image", "dep:image"]
 
 [dependencies]
 ratatui = "0.29"
@@ -28,6 +29,8 @@ chrono = "0.4"
 open = { version = "5.0", optional = true }
 arboard = { version = "3.4", optional = true }
 notify-rust = { version = "4.11", optional = true }
+ratatui-image = { version = "8.1", optional = true, features = ["image-defaults"] }
+image = { version = "0.25", optional = true }
 toml = "0.8"
 dirs = "5.0"
 thiserror = "1.0"