Message context menus, titled threads, emoji channels, and better markdown

Messages now have a context menu, and the composer can dismiss all link previews in one action. Copying a message link confirms the action beside the control instead of sending a toast to the bottom of the screen.

Channels can use emoji in their names. Threads gain Slack-style titles, images stay within the thread panel, and specialist dispatch uses the full thread history so a reply keeps the conversation that led to it.

Project creation preserves local repository setup and refreshes channel worktrees correctly. Workspace scope is enforced on notification routes, voice loads its audio worklet from the bundled app assets, and the login flow no longer adds a redundant success toast after logout.

Loose markdown lists now render as lists instead of collapsing into ordinary paragraphs. The unread divider aligns with the first unread content, and Browse Channels tracks join state per room instead of reusing stale dialog state.

Incoming direct messages can play a notification sound. Emoji channel names use one allowlist for creation and rename, and the desktop app icon keeps its transparent background.

The old package Marketplace entries are removed as the app transitions to its newer app distribution model.