feat(agent-manager): regroup toolbar actions

[marius-kilocode]

What Problem This Solves

The Agent Manager tab toolbar mixed worktree commands, review controls, optional session panels, runtime tools, and fullscreen review in an unstable order. Optional controls could shift frequently used buttons, the toolbar fullscreen action duplicated the Changes panel header action, disabled Apply looked interactive, and toolbar icons used inconsistent visual weights.

Why This Change Was Made

• Group Documents and Subagents as optional session-panel handles on the left, with a separator that only renders when either panel exists.
• Keep the workbench controls stable on the right in this order: Changes, PR, Apply, Open in VS Code, Browser, Run, Terminal.
• Keep Run and Terminal adjacent because Run sends output to the configured terminal destination. Browser stays in the workbench because both the agent and user can use it to test localhost applications.
• Remove the duplicate fullscreen button from the toolbar. Fullscreen review remains available from the Changes panel header.
• Add tab_toolbar PostHog telemetry for PR, Apply, Documents, Subagents, and Browser, alongside the existing toolbar events, so future button removals can be data-driven.
• Normalize Agent Manager toolbar outline icons to an effective 1px stroke at 16px, redraw the PR icon as a matching outline glyph, dim disabled icons, remove the disabled pointer cursor, and remove the green Run-active tint.
• Track the shared icon-button migration in follow-up issue Unify VS Code icon button styling in a shared design system #13915.

User Impact

The toolbar keeps its main workbench controls in stable positions as optional panels appear. Disabled Apply is visibly disabled while its tooltip remains available to explain why. Open-panel active states remain highlighted. Running uses the normal icon colour and the play/stop glyph change to communicate state.

Evidence

Before

After

Disabled Apply

Changes panel open

Validation completed:

• bun run compile in packages/kilo-vscode/
• bun test tests/unit/agent-manager-telemetry.test.ts tests/unit/agent-manager-terminal-side.test.ts, 27 passed
• Isolated VS Code self-test against the same shadow workspace and worktrees before and after the change
• Verified computed icon stroke values, disabled Apply colour and cursor, Changes active state, and tooltip behaviour

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (8 files)

• .changeset/agent-manager-toolbar-groups.md
• packages/kilo-docs/public/img/screenshot-tests/kilo-vscode/visual-regression/agentmanager/tab-bar-full-context-chromium-linux.png
• packages/kilo-docs/public/img/screenshot-tests/kilo-vscode/visual-regression/agentmanager/tab-bar-with-review-tab-chromium-linux.png
• packages/kilo-ui/src/components/icon.tsx
• packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx
• packages/kilo-vscode/webview-ui/agent-manager/TabBar.tsx
• packages/kilo-vscode/webview-ui/agent-manager/agent-manager.css
• packages/kilo-vscode/webview-ui/src/stories/agent-manager.stories.tsx

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_{Reviewed by grok-4.6 · Input: 184.7K · Output: 17.6K · Cached: 558.5K}

_{Review guidance: REVIEW.md from base branch main}