feat: Redesign review tab with phase selection, commit navigation, and consolidated toolbar

- Add BranchManager.listCommits() and diffCommit() for commit-level navigation
- Add getPhaseReviewCommits and getCommitDiff tRPC procedures
- New ReviewHeader: consolidated toolbar with phase selector pills, branch info,
  stats, integrated preview controls, and approve/reject actions
- New CommitNav: horizontal commit strip with "All changes" + individual commits,
  each showing hash, message, and change stats
- Slim down ReviewSidebar: file list only with dimming for out-of-scope files
  when viewing a single commit
- ReviewTab orchestrates all pieces in a single bordered card layout

apps/server/git/branch-manager.ts

@@ -6,7 +6,7 @@
  * a worktree to be checked out.
  */
 
-import type { MergeResult } from './types.js';
+import type { MergeResult, BranchCommit } from './types.js';
 
 export interface BranchManager {
   /**
@@ -45,4 +45,15 @@ export interface BranchManager {
    * since local branches may not include all remote branches.
    */
   remoteBranchExists(repoPath: string, branch: string): Promise<boolean>;
+
+  /**
+   * List commits that headBranch has but baseBranch doesn't.
+   * Used for commit-level navigation in code review.
+   */
+  listCommits(repoPath: string, baseBranch: string, headBranch: string): Promise<BranchCommit[]>;
+
+  /**
+   * Get the raw unified diff for a single commit.
+   */
+  diffCommit(repoPath: string, commitHash: string): Promise<string>;
 }

apps/server/git/simple-git-branch-manager.ts

@@ -11,7 +11,7 @@ import { mkdtempSync, rmSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { simpleGit } from 'simple-git';
 import type { BranchManager } from './branch-manager.js';
-import type { MergeResult } from './types.js';
+import type { MergeResult, BranchCommit } from './types.js';
 import { createModuleLogger } from '../logger/index.js';
 
 const log = createModuleLogger('branch-manager');
@@ -116,4 +116,28 @@ export class SimpleGitBranchManager implements BranchManager {
       return false;
     }
   }
+
+  async listCommits(repoPath: string, baseBranch: string, headBranch: string): Promise<BranchCommit[]> {
+    const git = simpleGit(repoPath);
+    const logResult = await git.log({ from: baseBranch, to: headBranch, '--stat': null });
+
+    return logResult.all.map((entry) => {
+      const diffStat = entry.diff;
+      return {
+        hash: entry.hash,
+        shortHash: entry.hash.slice(0, 7),
+        message: entry.message,
+        author: entry.author_name,
+        date: entry.date,
+        filesChanged: diffStat?.files?.length ?? 0,
+        insertions: diffStat?.insertions ?? 0,
+        deletions: diffStat?.deletions ?? 0,
+      };
+    });
+  }
+
+  async diffCommit(repoPath: string, commitHash: string): Promise<string> {
+    const git = simpleGit(repoPath);
+    return git.diff([`${commitHash}~1`, commitHash]);
+  }
 }

apps/server/git/types.ts

@@ -58,6 +58,33 @@ export interface MergeResult {
   message: string;
 }
 
+// =============================================================================
+// Branch Commit Info
+// =============================================================================
+
+/**
+ * Represents a single commit in a branch's history.
+ * Used for commit-level navigation in code review.
+ */
+export interface BranchCommit {
+  /** Full commit hash */
+  hash: string;
+  /** Short commit hash (7 chars) */
+  shortHash: string;
+  /** First line of commit message */
+  message: string;
+  /** Author name */
+  author: string;
+  /** ISO date string */
+  date: string;
+  /** Number of files changed */
+  filesChanged: number;
+  /** Number of insertions */
+  insertions: number;
+  /** Number of deletions */
+  deletions: number;
+}
+
 // =============================================================================
 // WorktreeManager Port Interface
 // =============================================================================

apps/server/trpc/routers/phase.ts

@@ -234,5 +234,69 @@ export function phaseProcedures(publicProcedure: ProcedureBuilder) {
         await orchestrator.approveAndMergePhase(input.phaseId);
         return { success: true };
       }),
+
+    getPhaseReviewCommits: publicProcedure
+      .input(z.object({ phaseId: z.string().min(1) }))
+      .query(async ({ ctx, input }) => {
+        const phaseRepo = requirePhaseRepository(ctx);
+        const initiativeRepo = requireInitiativeRepository(ctx);
+        const projectRepo = requireProjectRepository(ctx);
+        const branchManager = requireBranchManager(ctx);
+
+        const phase = await phaseRepo.findById(input.phaseId);
+        if (!phase) {
+          throw new TRPCError({ code: 'NOT_FOUND', message: `Phase '${input.phaseId}' not found` });
+        }
+        if (phase.status !== 'pending_review') {
+          throw new TRPCError({ code: 'BAD_REQUEST', message: `Phase is not pending review (status: ${phase.status})` });
+        }
+
+        const initiative = await initiativeRepo.findById(phase.initiativeId);
+        if (!initiative?.branch) {
+          throw new TRPCError({ code: 'BAD_REQUEST', message: 'Initiative has no branch configured' });
+        }
+
+        const initBranch = initiative.branch;
+        const phBranch = phaseBranchName(initBranch, phase.name);
+        const projects = await projectRepo.findProjectsByInitiativeId(phase.initiativeId);
+
+        const allCommits: Array<{ hash: string; shortHash: string; message: string; author: string; date: string; filesChanged: number; insertions: number; deletions: number }> = [];
+
+        for (const project of projects) {
+          const clonePath = await ensureProjectClone(project, ctx.workspaceRoot!);
+          const commits = await branchManager.listCommits(clonePath, initBranch, phBranch);
+          allCommits.push(...commits);
+        }
+
+        return { commits: allCommits, sourceBranch: phBranch, targetBranch: initBranch };
+      }),
+
+    getCommitDiff: publicProcedure
+      .input(z.object({ phaseId: z.string().min(1), commitHash: z.string().min(1) }))
+      .query(async ({ ctx, input }) => {
+        const phaseRepo = requirePhaseRepository(ctx);
+        const projectRepo = requireProjectRepository(ctx);
+        const branchManager = requireBranchManager(ctx);
+
+        const phase = await phaseRepo.findById(input.phaseId);
+        if (!phase) {
+          throw new TRPCError({ code: 'NOT_FOUND', message: `Phase '${input.phaseId}' not found` });
+        }
+
+        const projects = await projectRepo.findProjectsByInitiativeId(phase.initiativeId);
+        let rawDiff = '';
+
+        for (const project of projects) {
+          const clonePath = await ensureProjectClone(project, ctx.workspaceRoot!);
+          try {
+            const diff = await branchManager.diffCommit(clonePath, input.commitHash);
+            if (diff) rawDiff += diff + '\n';
+          } catch {
+            // commit not in this project clone
+          }
+        }
+
+        return { rawDiff };
+      }),
   };
 }