feat: Add ASCII art size selection for image attachments and enhance message context menu

docs/changelog/v0.2.12.md

@@ -18,6 +18,7 @@ Private channels are now genuinely private: password-protected channels are end-
   - Each image attachment renders its own ASCII preview with its own "save original" action; audio/file attachments each get their own play/download line.
   - In encrypted channels every attachment is encrypted individually (blob + ASCII preview), and the caption is room-encrypted — the server still stores only ciphertext and can report count/size but not contents.
   - Up to 10 attachments per message.
+- **Right-click message menu** — right-click any message for a context menu: save/download/play its attachment, mention the sender, view their profile, copy the text, or delete the message. (Keyboard: F6 focuses the message list for arrow-key selection + Delete.) The selected message is now highlighted while the list is focused.
 - **Message deletion** — press Delete on a selected message to remove it. You can always delete your own messages; moderators and above can delete others' messages, but only from users **below their own role** (a mod can't delete an admin's or owner's message). Deleting a message also removes its attachment blobs from server storage.
 - **Customizable download folder** — `/downloadpath` opens your OS-native folder picker (Windows Explorer / macOS Finder / Linux GTK or KDE) to choose where downloaded attachments and saved images go; `/downloadpath <path>` sets it directly (the fallback when no native picker is available). Downloaded files now land in that folder (with automatic `(n)` de-duplication) instead of a temp directory.
 - `/join <channel> [password]` — join protected channels inline, or let the client prompt: joining a protected channel without a password opens a masked prompt that re-prompts on a wrong password
@@ -25,11 +26,13 @@ Private channels are now genuinely private: password-protected channels are end-
 - IRC `MODE` implemented — `MODE #chan` reports `+k`/`+`, `MODE #chan +k <key>` sets and `-k` clears the room password (channel creator or admin only), ban-list probes get a clean empty reply, and `CHANMODES` is advertised in ISUPPORT
 - IRC `TOPIC` set support — the channel creator can change the topic from IRC; the change broadcasts to connected TUI clients (previously topic changes were rejected with a stub error)
 - Attach a file by drag & drop or by pasting — drop a file onto the terminal, or **copy a file in your file manager and press Ctrl+V**, to stage it as an attachment (the next Enter sends it with your caption). Multiple files at once are supported. Ctrl+V still pastes text when the clipboard holds text; Ctrl+Y is a paste alias. On Windows the copied-file paste reads the clipboard's file list directly (Windows Terminal never pastes copied files as text), with `xclip`/`wl-paste` used on Linux
+- Pick ASCII-art size for attached images — `/size` opens a Small/Medium/Large picker (40×40 / 80×80 / 120×120) with descriptions, `/size <s|m|l>` sets it directly, and `/send <file> -l` sets it for that message. The choice is a saved preference and applies to copy-paste/drag-drop images (which have no per-file flag); the current size is shown in the staging tray
 - New `TransparentLight` theme — dark characters on a transparent background, for light terminal color schemes (`/theme transparentlight`)
 - Timestamps in messages are now aware of the current culture and display the short time pattern for today's messages and the short date+time pattern for older messages.
 
 ## Bug Fixes
 
+- Attachments whose files have been pruned (retention cleanup deletes blobs older than `Storage:RetentionDays` but left the message rows) no longer render a dead download/preview. When channel history loads, the server checks which attachment blobs still exist: missing ones are dropped from the message, and an attachment-only message whose files are all gone is removed from the database.
 - Fixed intermittent crash on Ctrl+W — Terminal.Gui binds Ctrl+W to clipboard-cut, and Windows clipboard contention (another app holding the clipboard) threw an unhandled `Win32Exception` that took the app down. Ctrl+W now deletes the previous word (readline behavior, no clipboard), and all clipboard shortcuts (Ctrl+X/C/V/Y) are guarded so transient clipboard failures log a warning instead of crashing
 - Fixed emoji shortcode replacement permanently disabling itself if a cursor update threw mid-replacement
 - IRC `LIST` no longer leaks private channels; protected channels are marked `[+k]`