feat: Enhance ThemeManager to ensure transparent themes render correctly for editable fields

docs/changelog/v0.2.12.md

@@ -18,7 +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.
+- **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, copy the message ID (for linking or command arguments), 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
@@ -32,6 +32,7 @@ Private channels are now genuinely private: password-protected channels are end-
 
 ## Bug Fixes
 
+- Transparent themes no longer draw an opaque box behind the message input. The input `TextView` renders with the `Editable` visual role, which Terminal.Gui derives as an opaque color when a theme leaves it unset; the themes now pin `Editable`/`ReadOnly` to their base colors so the input matches its (transparent) background.
 - 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

src/EchoHub.Client/Themes/ThemeManager.cs

@@ -575,7 +575,14 @@ public static class ThemeManager
             Focus = focus,
             HotNormal = normal,
             HotFocus = focus,
-            Disabled = normal
+            Disabled = normal,
+
+            // TextView/TextField draw their editable area with the Editable/ReadOnly roles. If
+            // left unset, Terminal.Gui derives an opaque background from Normal — which renders
+            // as a solid box behind the input under transparent themes. Pin them to the theme's
+            // own colors so the input matches its background (transparent stays transparent).
+            Editable = normal,
+            ReadOnly = normal
         };
     }