feat(tui): redesign layout per spec v2 — 3-panel top row, 4-mode input bar, tamboui 0.3.0

- Layout: status bar (borderless), horizontal top row (sessions 30% / active 30% / tools 40%), router fill, input bar fixed
- Components: rewrote all 5 + added ToolsPanel; all accept TuiState directly
- InputBar: 4 modes (ROUTER/NAVIGATE/FILTER/STEER) with context-sensitive keybind hints
- RouterPanel: inline approval/event overlays as last-child text panels
- StatusBar: borderless row with model, providerType, session count, approval badge
- SessionList: manual column/row rendering, no list widget, overflow truncation
- tamboui bumped to 0.3.0
- TambouiKeyMapper: ctrl+key required for all keybinds, bare chars always
  go to input buffer.
- KeyResolver: Quit is ROUTER-only (not global); NavUp/NavDown handled in
  ROUTER as well as NAVIGATE; Filter in ROUTER maps to OpenFilter; CharInput
  in ROUTER returns null (semantic chars handled upstream by mapper).

apps/tui/build.gradle

@@ -29,7 +29,7 @@ dependencies {
     implementation "io.ktor:ktor-client-websockets:$ktor_version"
     implementation "io.ktor:ktor-client-logging:$ktor_version"
 
-    implementation platform('dev.tamboui:tamboui-bom:0.2.1-SNAPSHOT')
+    implementation platform('dev.tamboui:tamboui-bom:0.3.0')
     implementation 'dev.tamboui:tamboui-tui'
     implementation 'dev.tamboui:tamboui-widgets'
     implementation 'dev.tamboui:tamboui-core'