Agentic UI: Simplify Sidebar with new Site-Centric Focus

[shaunandrews]

Related issues

• None

How AI was used in this PR

Codex helped extract and iterate on the site-centric Agentic UI sidebar, then verified the final branch with linting, typecheck, targeted tests, and a running local app session. The PR remains draft because it is a visual/navigation change that needs human review in the app.

Executive summary

This PR simplifies Agentic UI around sites as the primary object. The sidebar no longer behaves like a chat list; it focuses on local sites, their status, and their latest conversation. Chat creation and chat history moved into the chat panel footer so previous conversations remain reachable without making the sidebar carry two navigation models.

Site rows now open the latest chat, or start a new site chat when no chat exists. Site settings remain available through the existing settings route.

Proposed Changes

• Makes the Agentic UI sidebar site-centric, with site rows focused on site names, run state, activity, and latest chat navigation.
• Adds chat-panel footer controls for chat history and new chat, including tooltips and the New Chat keyboard shortcut.
• Keeps the sidebar collapsed/open toggle aligned with the same footer control row and removes opacity/hover complexity from the sidebar footer account/toggle controls.
• Keeps the preview panel governed by the user's preview toggle on preview-capable chat routes.

Review guide

• Review the sidebar behavior first: selecting a site should open its latest active chat, stopped/running site controls should still work, and settings-context styling should not make the site row look like the active chat.
• Review the new chat/history footer controls in narrow and wide chat panels, with the sidebar open and closed. The controls should align with nearby footer controls and should not collide with the composer.
• Review keyboard and tooltip behavior for New Chat and Chat History.
• Review light and dark appearances because this is primarily layout and visual polish.

Okay to skim

• Mechanical cleanup of no-longer-used route, connector, query, and type plumbing.
• CSS cleanup that only removes styles for deleted sidebar-row affordances.

Diff breakdown

• Sidebar and site list: site-centric rows, row action cleanup, footer alignment updates.
• Chat panel: footer actions for history and new chat, plus tests for ordering, labels, tooltips, timestamps, and shortcut behavior.
• Routing/data: simplified site navigation and removed unused data paths.
• Tests: updated site list and footer action coverage around the new navigation model.

Known tradeoffs and follow-ups

• Any additional site-level actions should move into clear existing surfaces rather than adding another sidebar navigation mode.
• The PR is still visual-heavy; reviewers should do a hands-on pass in both color schemes.
• Existing local runtime noise was observed during app launch, including the known allowpopups warning. No new typecheck or targeted test failures were observed.

Safety checklist

• Feature-flag/gating: limited to Agentic UI paths in apps/ui.
• Data migrations or persistence changes: none.
• API compatibility: only unused Agentic UI data plumbing was removed.
• Default UI impact: changes Agentic UI navigation and footer controls only.
• Performance: removes an unused site-details data path.
• Security and privacy: no new data collection or credential handling.
• Rollback plan: revert this PR or the final refinement commit to restore the previous sidebar/chat behavior.
• Human visual review completed in light and dark mode.

Testing Instructions

• Run npm run typecheck.
• Run npm test -- apps/ui/src/components/site-list/index.test.tsx apps/ui/src/components/user-menu/index.test.tsx apps/ui/src/components/sidebar-layout/index.test.tsx apps/ui/src/ui-classic/components/session-view/session-chat-actions.test.tsx.
• Run npm start and confirm Studio launches from this branch.
• In the app, review the site-centric sidebar, site run controls, collapsed/open sidebar toggle, chat history control, New chat control, and composer/footer alignment in both light and dark appearances.

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?