Sækja codeg 0.19.0

- perf(streaming): Streaming replies do far less work per token. Only the turn being written is recomputed, so long, fast responses stay smooth.
- perf(streaming): The conversation view no longer re-renders on every streamed token. It updates only from the fields it displays.
- perf(sessions): A session streaming in the background no longer slows the one you're watching. State moved to fine-grained stores that update only the affected panels.
- perf(agents): The installed-agent list is fetched once and shared instead of rescanned per component on every window focus.
- perf(git): The Git panel opens instantly on huge change sets. Very large change lists cap at 500 rows with a one-click reveal.
- perf(diff): Enormous diffs open without locking the UI. Previews render the first 500 lines with a "show the rest" button.
- perf(history): Conversation and folder lists load faster as history grows. Per-file summaries are cached instead of re-parsed on every listing.
- perf(startup): Text-only sessions load lighter and faster. The highlighting, math, and diagram engines (~10 MB) load only when actually used.
- perf(acp): Lower overhead while events stream. Event sizes are estimated structurally instead of serialized under the session lock.
- feat(editor): Long lines can now wrap in the editors. Toggle word wrap (off by default) from the right-click menu, Alt+Z, or Fonts settings.
- feat(composer): Paste as plain text with Ctrl/Cmd+Shift+V, skipping the usual Markdown/rich-text conversion.
- feat(appearance): Hide the mode cards on the new-conversation screen with a new Appearance setting (on by default).
- fix(chat): The per-reply files card stays compact — created and changed files now share one bounded, scrollable area.
- chore(experts): Bundled expert skills refreshed to Superpowers 6.1.1.
- chore(acp): Bundled agents updated — CodeBuddy 2.117.0 and Kimi Code 0.22.3.