feat: AI flow builder, visibility model, dashboard tabs, fork UI (#88)

- AI flow builder: scaffold → branch detail → assemble → review flow
- Generate All one-click branch generation with stop/cancel
- Regenerate scaffold suggestions button
- 3-action review screen: Start Flow, Open in Editor, Build Another
- Fix Publish button gated behind !isDirty
- Fix visibility column enforcement in tree access filter
- Add ?visibility filter and author_name to GET /trees
- Dashboard tabbed flows: My Flows / My Team / Public / All
- Create button in My Flows tab, window focus reload (stale data fix)
- Fork UI with optional reason modal
- Fix account_id nullability in User type and schema
- Keep is_public and visibility in sync on updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/ForgotPasswordPage.tsx

@@ -35,7 +35,7 @@ export function ForgotPasswordPage() {
               <BrandLogo size="lg" className="h-10 w-10 invert sm:h-12 sm:w-12" />
             </div>
           </div>
-          <h1 className="text-3xl font-bold text-foreground tracking-tight">
+          <h1 className="text-3xl font-bold font-heading text-foreground tracking-tight">
             Reset Password
           </h1>
           <p className="mt-2 text-sm text-muted-foreground">