Restore features lost during main merge and fix workspace setup flow

Restores all features dropped when merging main into dev:
- Keyboard shortcuts (send, dictation-confirm) with full e2e chain
- Feature toggles (plan/fast mode) in agent status bar
- Sidebar kebab menu (Remove Project) on project rows
- Combined model selector (sticky header, sizing, favorites sort, search)
- Question form Enter key submit with guard
- Input focus restoration (composer + AgentStatusBar onDropdownClose)
- Draft-agent feature toggles and focus restoration
- Provider diagnostics UI (settings section, diagnostic sheet, status badge)
- Provider diagnostics server (snapshot manager, diagnostic utils, RPC)

Fixes dev-branch regressions:
- New workspace button now opens composer in setup dialog via beginWorkspaceSetup
- Setup tab auto-opens when workspace setup is running

packages/app/src/screens/workspace/workspace-draft-agent-config.ts

@@ -6,6 +6,7 @@ export function buildWorkspaceDraftAgentConfig(input: {
   modeId?: string;
   model?: string;
   thinkingOptionId?: string;
+  featureValues?: Record<string, unknown>;
 }): AgentSessionConfig {
   return {
     provider: input.provider,
@@ -13,5 +14,6 @@ export function buildWorkspaceDraftAgentConfig(input: {
     ...(input.modeId ? { modeId: input.modeId } : {}),
     ...(input.model ? { model: input.model } : {}),
     ...(input.thinkingOptionId ? { thinkingOptionId: input.thinkingOptionId } : {}),
+    ...(input.featureValues ? { featureValues: input.featureValues } : {}),
   };
 }