feat(ui): redesign workspace shell with context panel, tabbed sidebars, and faster diff UX (#433)

* feat: tabbed right sidebar, context panel, floating diff comments

* fix: auto-close left sidebar when context panel opens

- Increase default context panel width from 520 to 600 pixels
- Increase sidebar minimum width from 200 to 300 pixels
- Replace collapsible component with custom button in diff view

* refactoring: rework sidebars, tabs, and file tree layout

- Rewrite AnimatedTabs as segment-style with sliding indicator
- Upgrade SidebarFilesTree to match FilesView features (context menus,
  git status, file icons, CRUD dialogs, fuzzy search ranking)
- Restructure FilesView header: tabs row + actions row, remove breadcrumbs
- Show relative path in context panel header, track active tab
- Allow left sidebar to stay open alongside context panel
- Hide diff/files tabs from header on desktop (mobile-only)
- Move chevron after group name in session sidebar
- Compact tab heights in right sidebar and git view
- Size PreviewToggleButton to match other action buttons
- Remove directory loading spinner from folder icons

* feat: add project icon and color customization

- Enable users to assign custom icons to projects
- Allow users to choose accent colors for projects
- Stabilize repo status UI during project switching

* feat: add scroll fade indicators to editor tabs

* style: reduce spacing and icon sizes in header

* style: adjust tab component padding from uniform to vertical-horizontal

* feat: Add session state indicators to project tabs

* feat: Enhance session status handling and improve UI responsiveness

* fix: preserve upstream tracking on branch rename

* fix: improve initial remote selection for pull requests

- Uses saved remote name from previous session when available
- Selects remote based on tracking branch when possible
- Falls back to origin or first available remote

* perf(diff): faster highlight, stable stacked scroll

- split/unified Pierre worker pools; prefer shiki-wasm
- align diff CSS line-height; disable scroll anchoring; drop WebKit compositing hacks
- harden stacked pin/align (cancel on user scroll/input); prevent overscroll
- make overlay scrollbar MutationObserver optional; disable for diff container

* feat: handle binary files in diff view

* fix: adjust project tabs layout and drag regions

* style: update drag overlay visual styling

* feat: enable number keys to switch projects in the sidebar

* fix: recognize octet-stream as text-based MIME type

* feat: add keyboard navigation to context panel

* feat: add session pinning to sidebar

- Pin important sessions to keep them at the top
- Pinned sessions persist across browser sessions

* refactor: move context usage display from chat input to header

packages/web/server/lib/git-service.js

@@ -1316,6 +1316,8 @@ export async function getRangeFiles(directory, { base, head } = {}) {
 
 const IMAGE_EXTENSIONS = ['png', 'jpg', 'jpeg', 'gif', 'svg', 'webp', 'ico', 'bmp', 'avif'];
 
+const BINARY_SNIFF_BYTES = 8192;
+
 function isImageFile(filePath) {
   const ext = filePath.split('.').pop()?.toLowerCase();
   return IMAGE_EXTENSIONS.includes(ext || '');
@@ -1337,6 +1339,67 @@ function getImageMimeType(filePath) {
   return mimeMap[ext] || 'application/octet-stream';
 }
 
+const parseIsBinaryFromNumstat = (raw) => {
+  const text = String(raw || '').trim();
+  if (!text) {
+    return false;
+  }
+
+  // Expected format: <added>\t<deleted>\t<path>
+  const firstLine = text.split('\n').map((line) => line.trim()).find(Boolean) || '';
+  const [added, deleted] = firstLine.split('\t');
+  return added === '-' || deleted === '-';
+};
+
+const looksBinaryBySniff = async (absolutePath) => {
+  try {
+    const handle = await fsp.open(absolutePath, 'r');
+    try {
+      const buffer = Buffer.alloc(BINARY_SNIFF_BYTES);
+      const { bytesRead } = await handle.read(buffer, 0, BINARY_SNIFF_BYTES, 0);
+      if (bytesRead <= 0) {
+        return false;
+      }
+      return buffer.subarray(0, bytesRead).includes(0);
+    } finally {
+      await handle.close();
+    }
+  } catch {
+    return false;
+  }
+};
+
+const isBinaryDiff = async (directoryPath, filePath, staged) => {
+  // Fast path: ask git for numstat. For binary, it returns "-\t-\t<path>".
+  const args = ['diff', '--numstat'];
+  if (staged) {
+    args.push('--cached');
+  }
+  args.push('--', filePath);
+
+  const result = await runGitCommand(directoryPath, args);
+  if (parseIsBinaryFromNumstat(result.stdout)) {
+    return true;
+  }
+
+  // Fallback for untracked files (diff output is empty): use --no-index against /dev/null
+  if (!staged) {
+    const tracked = await runGitCommand(directoryPath, ['ls-files', '--error-unmatch', '--', filePath]).then((r) => r.success);
+    if (!tracked) {
+      const noIndex = await runGitCommand(directoryPath, ['diff', '--no-index', '--numstat', '--', '/dev/null', filePath]);
+      if (parseIsBinaryFromNumstat(noIndex.stdout) || parseIsBinaryFromNumstat(noIndex.stderr) || parseIsBinaryFromNumstat(noIndex.message)) {
+        return true;
+      }
+      const text = `${noIndex.stdout || ''}\n${noIndex.stderr || ''}\n${noIndex.message || ''}`.toLowerCase();
+      if (text.includes('binary files') || text.includes('git binary patch')) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+};
+
 export async function getFileDiff(directory, { path: filePath, staged = false } = {}) {
   if (!directory || !filePath) {
     throw new Error('directory and path are required for getFileDiff');
@@ -1347,6 +1410,20 @@ export async function getFileDiff(directory, { path: filePath, staged = false }
   const isImage = isImageFile(filePath);
   const mimeType = isImage ? getImageMimeType(filePath) : null;
 
+  if (!isImage) {
+    const absolutePath = path.join(directoryPath, filePath);
+    const isBinaryBySniff = await looksBinaryBySniff(absolutePath);
+    const isBinary = isBinaryBySniff || (await isBinaryDiff(directoryPath, filePath, staged));
+    if (isBinary) {
+      return {
+        original: '',
+        modified: '',
+        path: filePath,
+        isBinary: true,
+      };
+    }
+  }
+
   let original = '';
   try {
     if (isImage) {
@@ -1396,6 +1473,7 @@ export async function getFileDiff(directory, { path: filePath, staged = false }
     original,
     modified,
     path: filePath,
+    isBinary: false,
   };
 }
 
@@ -2381,8 +2459,42 @@ export async function renameBranch(directory, oldName, newName) {
   const git = await createGit(directory);
 
   try {
+    const normalizedOldName = cleanBranchName(String(oldName || '').trim());
+    const normalizedNewName = cleanBranchName(String(newName || '').trim());
+
+    const previousRemote = await git
+      .raw(['config', '--get', `branch.${normalizedOldName}.remote`])
+      .then((value) => String(value || '').trim())
+      .catch(() => '');
+    const previousMerge = await git
+      .raw(['config', '--get', `branch.${normalizedOldName}.merge`])
+      .then((value) => String(value || '').trim())
+      .catch(() => '');
+
     // Use git branch -m command to rename the branch
     await git.raw(['branch', '-m', oldName, newName]);
+
+    if (previousRemote && previousMerge && normalizedNewName) {
+      const previousMergeBranch = cleanBranchName(previousMerge);
+      const nextMergeBranch =
+        previousMergeBranch === normalizedOldName
+          ? normalizedNewName
+          : previousMergeBranch;
+      const upstream = normalizeUpstreamTarget(previousRemote, nextMergeBranch);
+
+      if (upstream) {
+        try {
+          await runGitCommandOrThrow(
+            directory,
+            ['branch', `--set-upstream-to=${upstream.full}`, normalizedNewName],
+            `Failed to set upstream to ${upstream.full}`
+          );
+        } catch {
+          await setBranchTrackingFallback(directory, normalizedNewName, upstream);
+        }
+      }
+    }
+
     return { success: true, branch: newName };
   } catch (error) {
     console.error('Failed to rename branch:', error);