fix(tui): align Ctrl+L and /model with classic CLI semantics

Make Ctrl+L non-destructive by redrawing the current screen state instead of starting a new session, and stop auto-appending --global for typed /model commands so session scope remains the default unless explicitly requested.

ui-tui/src/app/slash/commands/session.ts

@@ -16,17 +16,9 @@ import { patchOverlayState } from '../../overlayStore.js'
 import { patchUiState } from '../../uiStore.js'
 import type { SlashCommand } from '../types.js'
 
-const GLOBAL_MODEL_FLAG_RE = /(?:^|\s)--global(?:\s|$)/
-
 const TUI_SESSION_MODEL_RE = new RegExp(`(?:^|\\s)${TUI_SESSION_MODEL_FLAG}(?:\\s|$)`)
 const TUI_SESSION_STRIP_RE = new RegExp(`\\s*${TUI_SESSION_MODEL_FLAG}\\b\\s*`, 'g')
 
-const persistedModelArg = (arg: string) => {
-  const trimmed = arg.trim()
-
-  return !trimmed || GLOBAL_MODEL_FLAG_RE.test(trimmed) ? trimmed : `${trimmed} --global`
-}
-
 const stripTuiSessionFlag = (trimmed: string) =>
   trimmed.replace(TUI_SESSION_STRIP_RE, ' ').replace(/\s+/g, ' ').trim()
 
@@ -41,7 +33,7 @@ const modelValueForConfigSet = (arg: string) => {
     return stripTuiSessionFlag(trimmed)
   }
 
-  return persistedModelArg(trimmed)
+  return trimmed
 }
 
 export const sessionCommands: SlashCommand[] = [

ui-tui/src/app/useInputHandlers.ts

@@ -379,13 +379,8 @@ export function useInputHandlers(ctx: InputHandlerContext): InputHandlerResult {
     }
 
     if (isAction(key, ch, 'l')) {
-      if (actions.guardBusySessionSwitch()) {
-        return
-      }
-
-      patchUiState({ status: 'forging session…' })
-
-      return actions.newSession()
+      clearSelection()
+      return patchUiState(state => ({ ...state }))
     }
 
     if (isVoiceToggleKey(key, ch)) {