feat: add config and keybindings for new ink terminal buffer mode

test: update test utils and resolve snapshot differences for ink changes

feat: refactor VirtualizedList to support static rendering and terminal buffers

feat: wire up AppContainer mouse mode and recording state for ink buffer

Fix stale ref in ScrollProvider breaking scrolling.

The ScrollProvider was getting stuck with a stale reference because the
`scrollables` Map was being registered and unregistered whenever the entry
identity changed. The underlying `ScrollableList` component dynamically created
a new ID which caused React remount cycles, while the `ScrollProvider` itself
suffered from state lag where the event handler ref was one tick behind the
actual registration.

This commit resolves these issues by:
1. Adding a stable `id` and `key` to `ScrollableList` in `MainContent.tsx`
2. Making `scrollablesRef` synchronously update in `ScrollProvider.tsx`
3. Using a proxy entry in `useScrollable` to avoid constant re-registering.

chore: add useEffect cleanup for ResizeObservers

Checkpoint fixing terminal buffer support.

Termina Serializer Optimization

packages/cli/src/ui/utils/__snapshots__/CodeColorizer.test.tsx.snap

@@ -3,5 +3,6 @@
 exports[`colorizeCode > does not let colors from ansi escape codes leak into colorized code 1`] = `
 "line 1
 line 2 with red background
-line 3"
+line 3
+"
 `;

packages/cli/src/ui/utils/ui-sizing.test.ts

@@ -21,6 +21,7 @@ describe('ui-sizing', () => {
       (expected, width, altBuffer) => {
         const mockConfig = {
           getUseAlternateBuffer: () => altBuffer,
+          getUseTerminalBuffer: () => false,
         } as unknown as Config;
         expect(calculateMainAreaWidth(width, mockConfig)).toBe(expected);
       },