feat: Replace horizontal commit nav with VSCode-style sidebar icon switcher

Move commit navigation from a horizontal strip into ReviewSidebar with a
vertical icon strip (Files/Commits views). Delete CommitNav.tsx.

apps/web/src/components/review/CommitNav.tsx

@@ -1,116 +0,0 @@
-import { GitCommitHorizontal, Plus, Minus, FileCode } from "lucide-react";
-import type { CommitInfo } from "./types";
-
-interface CommitNavProps {
-  commits: CommitInfo[];
-  selectedCommit: string | null; // null = "all changes"
-  onSelectCommit: (hash: string | null) => void;
-  isLoading: boolean;
-}
-
-export function CommitNav({
-  commits,
-  selectedCommit,
-  onSelectCommit,
-  isLoading,
-}: CommitNavProps) {
-  if (isLoading || commits.length === 0) return null;
-
-  return (
-    <div className="border-b border-border/50 bg-muted/20">
-      <div className="flex items-center gap-0 px-4 overflow-x-auto">
-        {/* "All changes" pill — only when multiple commits */}
-        {commits.length > 1 && (
-          <>
-            <CommitPill
-              label="All changes"
-              sublabel={`${commits.length} commits`}
-              isActive={selectedCommit === null}
-              onClick={() => onSelectCommit(null)}
-            />
-            <div className="w-px h-5 bg-border mx-1 shrink-0" />
-          </>
-        )}
-
-        {/* Individual commit pills - most recent first */}
-        {commits.map((commit) => (
-          <CommitPill
-            key={commit.hash}
-            label={commit.shortHash}
-            sublabel={truncateMessage(commit.message)}
-            stats={{ files: commit.filesChanged, add: commit.insertions, del: commit.deletions }}
-            isActive={selectedCommit === commit.hash}
-            onClick={() => onSelectCommit(commit.hash)}
-            isMono
-          />
-        ))}
-      </div>
-    </div>
-  );
-}
-
-interface CommitPillProps {
-  label: string;
-  sublabel: string;
-  stats?: { files: number; add: number; del: number };
-  isActive: boolean;
-  onClick: () => void;
-  isMono?: boolean;
-}
-
-function CommitPill({
-  label,
-  sublabel,
-  stats,
-  isActive,
-  onClick,
-  isMono,
-}: CommitPillProps) {
-  return (
-    <button
-      onClick={onClick}
-      className={`
-        flex items-center gap-2 px-3 py-2 text-[11px] whitespace-nowrap
-        transition-colors duration-fast border-b-2 shrink-0
-        ${isActive
-          ? "border-primary text-foreground"
-          : "border-transparent text-muted-foreground hover:text-foreground hover:bg-muted/50"
-        }
-      `}
-    >
-      {isMono ? (
-        <GitCommitHorizontal className="h-3 w-3 shrink-0 text-muted-foreground" />
-      ) : null}
-
-      <span className={isMono ? "font-mono font-medium" : "font-medium"}>
-        {label}
-      </span>
-
-      <span className="text-muted-foreground truncate max-w-[180px]">
-        {sublabel}
-      </span>
-
-      {stats && stats.files > 0 && (
-        <span className="flex items-center gap-1.5 text-[10px]">
-          <span className="flex items-center gap-0.5 text-muted-foreground">
-            <FileCode className="h-2.5 w-2.5" />
-            {stats.files}
-          </span>
-          <span className="flex items-center gap-0 text-diff-add-fg">
-            <Plus className="h-2.5 w-2.5" />
-            {stats.add}
-          </span>
-          <span className="flex items-center gap-0 text-diff-remove-fg">
-            <Minus className="h-2.5 w-2.5" />
-            {stats.del}
-          </span>
-        </span>
-      )}
-    </button>
-  );
-}
-
-function truncateMessage(msg: string): string {
-  const firstLine = msg.split("\n")[0];
-  return firstLine.length > 50 ? firstLine.slice(0, 47) + "..." : firstLine;
-}

apps/web/src/components/review/ReviewSidebar.tsx

@@ -1,3 +1,4 @@
+import { useState } from "react";
 import {
   MessageSquare,
   FileCode,
@@ -5,8 +6,12 @@ import {
   Minus,
   Circle,
   CheckCircle2,
+  GitCommitHorizontal,
+  Layers,
 } from "lucide-react";
-import type { FileDiff, ReviewComment } from "./types";
+import type { FileDiff, ReviewComment, CommitInfo } from "./types";
+
+type SidebarView = "files" | "commits";
 
 interface ReviewSidebarProps {
   files: FileDiff[];
@@ -14,6 +19,8 @@ interface ReviewSidebarProps {
   onFileClick: (filePath: string) => void;
   selectedCommit: string | null;
   activeFiles: FileDiff[];
+  commits: CommitInfo[];
+  onSelectCommit: (hash: string | null) => void;
 }
 
 export function ReviewSidebar({
@@ -22,11 +29,107 @@ export function ReviewSidebar({
   onFileClick,
   selectedCommit,
   activeFiles,
+  commits,
+  onSelectCommit,
 }: ReviewSidebarProps) {
+  const [view, setView] = useState<SidebarView>("files");
+
+  return (
+    <div className="flex h-full">
+      {/* Content panel */}
+      <div className="flex-1 min-w-0 overflow-y-auto">
+        {view === "files" ? (
+          <FilesView
+            files={files}
+            comments={comments}
+            onFileClick={onFileClick}
+            selectedCommit={selectedCommit}
+            activeFiles={activeFiles}
+          />
+        ) : (
+          <CommitsView
+            commits={commits}
+            selectedCommit={selectedCommit}
+            onSelectCommit={onSelectCommit}
+          />
+        )}
+      </div>
+
+      {/* Icon strip — right edge */}
+      <div className="flex flex-col items-center w-9 shrink-0 border-l border-border/50 py-1.5 gap-0.5">
+        <IconTab
+          icon={FileCode}
+          label="Files"
+          active={view === "files"}
+          onClick={() => setView("files")}
+        />
+        <IconTab
+          icon={GitCommitHorizontal}
+          label="Commits"
+          active={view === "commits"}
+          onClick={() => setView("commits")}
+          badge={commits.length > 1 ? commits.length : undefined}
+        />
+      </div>
+    </div>
+  );
+}
+
+/* ─── Icon Tab ─────────────────────────────────────────── */
+
+function IconTab({
+  icon: Icon,
+  label,
+  active,
+  onClick,
+  badge,
+}: {
+  icon: typeof FileCode;
+  label: string;
+  active: boolean;
+  onClick: () => void;
+  badge?: number;
+}) {
+  return (
+    <button
+      onClick={onClick}
+      title={label}
+      className={`
+        relative flex items-center justify-center w-8 h-8 rounded-md
+        transition-all duration-150
+        ${active
+          ? "text-primary bg-primary/10 shadow-[inset_2px_0_0_0] shadow-primary"
+          : "text-muted-foreground hover:text-foreground hover:bg-accent/50"
+        }
+      `}
+    >
+      <Icon className="h-[15px] w-[15px]" />
+      {badge !== undefined && (
+        <span className="absolute -top-0.5 -right-0.5 min-w-[14px] h-[14px] rounded-full bg-primary text-primary-foreground text-[9px] font-semibold flex items-center justify-center px-0.5 leading-none">
+          {badge}
+        </span>
+      )}
+    </button>
+  );
+}
+
+/* ─── Files View ───────────────────────────────────────── */
+
+function FilesView({
+  files,
+  comments,
+  onFileClick,
+  selectedCommit,
+  activeFiles,
+}: {
+  files: FileDiff[];
+  comments: ReviewComment[];
+  onFileClick: (filePath: string) => void;
+  selectedCommit: string | null;
+  activeFiles: FileDiff[];
+}) {
   const unresolvedCount = comments.filter((c) => !c.resolved).length;
   const resolvedCount = comments.filter((c) => c.resolved).length;
-
-  // Build a set of files visible in the current diff view
   const activeFilePaths = new Set(activeFiles.map((f) => f.newPath));
 
   return (
@@ -113,9 +216,101 @@ export function ReviewSidebar({
   );
 }
 
-/** Show filename with parent directory for context */
+/* ─── Commits View ─────────────────────────────────────── */
+
+function CommitsView({
+  commits,
+  selectedCommit,
+  onSelectCommit,
+}: {
+  commits: CommitInfo[];
+  selectedCommit: string | null;
+  onSelectCommit: (hash: string | null) => void;
+}) {
+  if (commits.length === 0) {
+    return (
+      <div className="flex items-center justify-center h-20 text-xs text-muted-foreground">
+        No commits
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-0.5">
+      <h4 className="text-[10px] font-semibold text-muted-foreground uppercase tracking-wider mb-1.5">
+        Commits
+      </h4>
+
+      {/* "All changes" — only when >1 commit */}
+      {commits.length > 1 && (
+        <button
+          onClick={() => onSelectCommit(null)}
+          className={`
+            flex w-full items-center gap-2 rounded px-2 py-1.5 text-left text-[11px]
+            transition-colors
+            ${selectedCommit === null
+              ? "bg-primary/10 text-primary"
+              : "text-muted-foreground hover:text-foreground hover:bg-accent/50"
+            }
+          `}
+        >
+          <Layers className="h-3 w-3 shrink-0" />
+          <span className="font-medium">All changes</span>
+          <span className="ml-auto text-[10px] opacity-70">
+            {commits.length} commits
+          </span>
+        </button>
+      )}
+
+      {/* Commit list */}
+      {commits.map((commit) => {
+        const isActive = selectedCommit === commit.hash;
+        return (
+          <button
+            key={commit.hash}
+            onClick={() => onSelectCommit(commit.hash)}
+            className={`
+              flex w-full flex-col gap-0.5 rounded px-2 py-1.5 text-left
+              transition-colors
+              ${isActive
+                ? "bg-primary/10 text-primary"
+                : "text-foreground hover:bg-accent/50"
+              }
+            `}
+          >
+            {/* Hash + stats */}
+            <div className="flex items-center gap-1.5 w-full">
+              <GitCommitHorizontal className={`h-3 w-3 shrink-0 ${isActive ? "text-primary" : "text-muted-foreground"}`} />
+              <span className="font-mono text-[11px] font-medium">
+                {commit.shortHash}
+              </span>
+              <span className="ml-auto flex items-center gap-1.5 text-[10px] shrink-0">
+                <span className="text-muted-foreground">{commit.filesChanged}f</span>
+                <span className="text-diff-add-fg">+{commit.insertions}</span>
+                <span className="text-diff-remove-fg">&minus;{commit.deletions}</span>
+              </span>
+            </div>
+
+            {/* Message */}
+            <span className={`text-[11px] truncate pl-[18px] ${isActive ? "text-primary/80" : "text-muted-foreground"}`}>
+              {truncateMessage(commit.message)}
+            </span>
+          </button>
+        );
+      })}
+    </div>
+  );
+}
+
+/* ─── Helpers ──────────────────────────────────────────── */
+
 function formatFilePath(path: string): string {
   const parts = path.split("/");
   if (parts.length <= 2) return path;
   return parts.slice(-2).join("/");
 }
+
+function truncateMessage(msg: string): string {
+  const firstLine = msg.split("\n")[0];
+  return firstLine.length > 50 ? firstLine.slice(0, 47) + "..." : firstLine;
+}

apps/web/src/components/review/ReviewTab.tsx

@@ -6,7 +6,6 @@ import { parseUnifiedDiff } from "./parse-diff";
 import { DiffViewer } from "./DiffViewer";
 import { ReviewSidebar } from "./ReviewSidebar";
 import { ReviewHeader } from "./ReviewHeader";
-import { CommitNav } from "./CommitNav";
 import type { ReviewComment, ReviewStatus, DiffLine } from "./types";
 
 interface ReviewTabProps {
@@ -235,14 +234,6 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
         preview={previewState}
       />
 
-      {/* Commit navigation strip */}
-      <CommitNav
-        commits={commits}
-        selectedCommit={selectedCommit}
-        onSelectCommit={setSelectedCommit}
-        isLoading={commitsQuery.isLoading}
-      />
-
       {/* Main content area */}
       {isDiffLoading ? (
         <div className="flex h-64 items-center justify-center text-muted-foreground gap-2">
@@ -278,6 +269,8 @@ export function ReviewTab({ initiativeId }: ReviewTabProps) {
               onFileClick={handleFileClick}
               selectedCommit={selectedCommit}
               activeFiles={files}
+              commits={commits}
+              onSelectCommit={setSelectedCommit}
             />
           </div>
         </div>

docs/frontend.md

@@ -111,10 +111,9 @@ The initiative detail page has three tabs managed via local state (not URL param
 ### Review Components (`src/components/review/`)
 | Component | Purpose |
 |-----------|---------|
-| `ReviewTab` | Review tab container — orchestrates header, commit nav, diff, sidebar, and preview |
+| `ReviewTab` | Review tab container — orchestrates header, diff, sidebar, and preview |
 | `ReviewHeader` | Consolidated toolbar: phase selector pills, branch info, stats, preview controls, approve/reject actions |
-| `CommitNav` | Horizontal commit navigation strip — "All changes" + individual commit pills with stats |
+| `ReviewSidebar` | VSCode-style icon strip (Files/Commits views) with file list, comment counts, and commit navigation |
-| `ReviewSidebar` | File list with comment counts, dimmed files when viewing single commit |
 | `DiffViewer` | Unified diff renderer with inline comments |
 | `PreviewPanel` | Docker preview status: building/running/failed with start/stop (legacy, now integrated into ReviewHeader) |
 | `ProposalCard` | Individual proposal display |