Feature/tui improvements (#71)

* refactor: encapsulate turn completion logic into a new ConversationTurn::finish method

* chore: ignore .freebuff directory in gitignore

* refactor: remove modular TUI components and consolidate UI code into single module

* refactor(tui): split the UI into terminal, input, action, state and view modules

main.rs was doing five jobs at once — terminal setup, input, key resolution,
rendering and cleanup — which is why the tree could not grow. The previous
attempt at a modular TUI collapsed into a 1,660-line app.rs before c1f1d38
removed it. Give each responsibility its own module so adding a screen is
additive rather than another round of untangling main.

- tui.rs owns the terminal. Raw mode, alternate screen, paste and focus modes
  and the keyboard protocol are switched on in one place and released by one
  idempotent restore(), reached from Drop, the panic hook and normal shutdown,
  so a panic or an early return can no longer strand a shell without echo.
- event.rs reads input on a dedicated thread and translates it into app events,
  dropping key releases so the keyboard protocol cannot fire a key twice.
- action.rs resolves key presses to named actions, reusing OpenCode's ctrl+x
  leader and action names so its bindings carry over. Adds ctrl+d and <leader>q.
- app.rs is the only place state changes; update() reports whether a repaint is
  needed, so an idle TUI does no work and a burst of events costs one frame.
- ui.rs stays pure, which is what will make a frame reproducible from TestBackend.

Renders now run inside a synchronized update so a slow repaint shows one whole
frame. Resize repaints explicitly instead of relying on an incidental redraw.

* feat: add theme system with generated landing site color palettes

* feat: render landing site wordmark and hairline lattice in TUI

* feat: add TUI menu, badge, input, and text components with updated view layout

* feat: add search filtering and left badge support to menus and terminal guards

* refactor: improve key resolution and prompt editing with byte-offset carets and text editing shortcuts

* feat: add session management, model selection, and tool execution tracking to TUI

* feat(tui): add markdown rendering, diff views, tool grouping, and mouse scroll

* feat(tui): load session history on resume and sync session metadata

Author: prem315

.gitignore

@@ -56,5 +56,11 @@ models.gen.json
 
 .alchemy
 
+.freebuff
+opencode.json
+
 # Rust build output (packages/tui binary; the launcher loads the built artifact).
 target
+
+# testing
+videos