Add intelligent handling for oversized photos in Telegram service

Implements send_large_photos_as_documents parameter to handle photos
exceeding Telegram's limits (10MB file size or 10000px dimension sum).

Features:
- Automatic detection of oversized photos using file size and PIL-based
  dimension checking
- Two handling modes:
  * send_large_photos_as_documents=false (default): Intelligently
    downsizes photos using Lanczos resampling and progressive JPEG
    quality reduction to fit within Telegram limits
  * send_large_photos_as_documents=true: Sends oversized photos as
    documents to preserve original quality
- For media groups: separates oversized photos and sends them as
  documents after the main group, or downsizes them inline
- Maintains backward compatibility with existing max_asset_data_size
  parameter for hard size limits

This resolves PHOTO_INVALID_DIMENSIONS errors for large images like
26MP photos while giving users control over quality vs. file size.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

README.md

@@ -214,6 +214,7 @@ data:
 | `chunk_delay` | Delay in milliseconds between sending multiple groups (0-60000). Useful for rate limiting. Default: 0 | No |
 | `wait_for_response` | Wait for Telegram to finish processing. Set to `false` for fire-and-forget (automation continues immediately). Default: `true` | No |
 | `max_asset_data_size` | Maximum asset size in bytes. Assets exceeding this limit will be skipped. Default: no limit | No |
+| `send_large_photos_as_documents` | Handle photos exceeding Telegram limits (10MB or 10000px dimension sum). If `true`, send as documents. If `false`, downsize to fit. Default: `false` | No |
 
 The service returns a response with `success` status and `message_id` (single message), `message_ids` (media group), or `groups_sent` (number of groups when split). When `wait_for_response` is `false`, the service returns immediately with `{"success": true, "status": "queued"}` while processing continues in the background.