feat(tui,dashboard,docs): add context command parity and context health panel

src/frontends/tui/commands.ts

@@ -6,6 +6,7 @@ export type Command =
   | { type: 'fullscreen' }
   | { type: 'compact' }
   | { type: 'usage' }
+  | { type: 'context' }
   | { type: 'verbose' }
   | { type: 'model'; name?: string; providerModel?: string }
   | { type: 'backend'; provider?: string }
@@ -55,6 +56,11 @@ export function parseCommand(input: string): Command | null {
     return { type: 'usage' };
   }
 
+  // Context
+  if (trimmed === '/context') {
+    return { type: 'context' };
+  }
+
   // Verbose
   if (trimmed === '/verbose') {
     return { type: 'verbose' };
@@ -162,6 +168,7 @@ Commands:
   /reset, /clear, /new   Clear conversation history
   /compact               Compact conversation history
   /usage                 Show token usage and estimated cost
+  /context               Show estimated context-window usage
   /verbose               Toggle verbose mode (show raw streaming and tool output)
   /status                Show session info and token usage
   /fullscreen, /fs       Switch to fullscreen mode
@@ -184,6 +191,7 @@ export const SLASH_COMMANDS = [
   '/new',
   '/compact',
   '/usage',
+  '/context',
   '/verbose',
   '/status',
   '/fullscreen',
@@ -207,6 +215,7 @@ export const COMMAND_TOOLTIPS: Record<string, string> = {
   '/new': 'Start a new conversation',
   '/compact': 'Compact conversation history to save context space',
   '/usage': 'Show token usage and estimated cost',
+  '/context': 'Show estimated context-window usage',
   '/verbose': 'Toggle verbose mode (show raw streaming and tool output)',
   '/status': 'Show session info and token usage',
   '/fullscreen': 'Switch to fullscreen mode',