Fixes "Message not found" error when editing immediately after sending.
**Problem**:
When sending a message, TDLib may return a temporary ID, then send
UpdateMessageSendSucceeded with the real server ID. We weren't handling
this update, so the cache kept the old ID while the server had a different
one, causing "Message not found" errors during edits.
**Solution**:
1. Added UpdateMessageSendSucceeded handler (client.rs:801-830)
- Finds message with temporary ID
- Replaces it with new message containing real server ID
- Preserves reply_info if present
2. Added validation before editing (main_input.rs:574-589)
- Checks message exists in cache
- Better error messages with chat_id and message_id
3. Added positive ID check in start_editing_selected (mod.rs:240)
- Blocks editing messages with temporary IDs (negative)
**Test**:
- Added test_edit_immediately_after_send (edit_message.rs:156-181)
- Verifies editing works right after send_message
- All 22 edit_message tests pass
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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