Revert sidebar navigation secondary sidebar change

[marius-kilocode]

Reverts PR #12894, which moved the Kilo sidebar navigation from the native VS Code title toolbar into the webview.

This restores the previous native sidebar navigation implementation and removes the webview top bar, related messages, translations, styles, story, screenshot baseline, and changeset.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Clean revert of #12894. Verified the reverted files (extension.ts command registrations, package.json view/title + editor/title menus, KiloProvider, options.ts, sidebar-worktree.ts, utils.ts, App.tsx, i18n, styles, story) are restored to the exact pre-#12894 state; the only remaining delta vs. that base comes from unrelated intermediate PR #12945 (Agent Manager terminal navigation). No dangling references to SidebarTopBar, openProfilePanel, KILO_TOP_BAR, hideTopBar/topBarSurface, or the sidebar.topBar.* i18n keys remain; all sidebarTitle.* wrapper commands delegate to registered commands and are pushed to context.subscriptions (no leaks); @vscode/codicons stays in bun.lock for kilo-docs; the deleted changeset belonged to an unreleased change, so none is needed for the revert.

Files Reviewed (37 files)

• .changeset/fix-secondary-sidebar-nav-bar.md (deleted)
• bun.lock
• packages/kilo-docs/public/img/screenshot-tests/kilo-vscode/visual-regression/chat/sidebar-top-bar-default-chromium-linux.png (deleted)
• packages/kilo-vscode/package.json
• packages/kilo-vscode/src/KiloProvider.ts
• packages/kilo-vscode/src/SettingsEditorProvider.ts
• packages/kilo-vscode/src/SubAgentViewerProvider.ts
• packages/kilo-vscode/src/extension.ts
• packages/kilo-vscode/src/kilo-provider/options.ts
• packages/kilo-vscode/src/kilo-provider/sidebar-worktree.ts
• packages/kilo-vscode/src/utils.ts
• packages/kilo-vscode/webview-ui/src/App.tsx
• packages/kilo-vscode/webview-ui/src/components/chat/SidebarTopBar.tsx (deleted)
• packages/kilo-vscode/webview-ui/src/i18n/ (20 locale files)
• packages/kilo-vscode/webview-ui/src/stories/chat.stories.tsx
• packages/kilo-vscode/webview-ui/src/styles/chat-layout.css
• packages/kilo-vscode/webview-ui/src/types/messages/webview-messages.ts

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_{Reviewed by kimi-k3 · Input: 70.3K · Output: 12.4K · Cached: 1.1M}

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