fix(dashboard): remove Lineage commit associations from Task Changes UI

The lineage commit associations panel surfaced low-value provenance
metadata. Remove the UI section, its dead state/fetch wiring in
TaskChangesTab, the orphaned .task-lineage-* CSS, and the obsolete
tests. The fetchTaskCommitAssociations API helper is retained.

packages/dashboard/app/components/TaskChangesTab.css

@@ -35,103 +35,3 @@
   box-shadow: none;
 }
 
-.task-lineage-associations {
-  display: flex;
-  flex-direction: column;
-  gap: var(--space-sm);
-  margin-bottom: var(--space-md);
-  padding: var(--space-sm);
-  border: 1px solid var(--border);
-  border-radius: var(--radius-md);
-  background: var(--surface);
-}
-
-.task-lineage-associations-header {
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  gap: var(--space-sm);
-}
-
-.task-lineage-associations-header h4 {
-  display: inline-flex;
-  align-items: center;
-  gap: var(--space-xs);
-  margin: 0;
-}
-
-.task-lineage-id,
-.task-lineage-sha {
-  font-family: var(--font-mono);
-  font-size: 0.75rem;
-}
-
-.task-lineage-associations-empty {
-  margin: 0;
-  color: var(--text-muted);
-}
-
-.task-lineage-associations-list {
-  display: flex;
-  flex-direction: column;
-  gap: var(--space-xs);
-}
-
-.task-lineage-association {
-  display: flex;
-  flex-direction: column;
-  gap: var(--space-xs);
-  padding: var(--space-sm);
-  border-radius: var(--radius-sm);
-  border: 1px solid var(--border);
-  background: var(--card);
-}
-
-.task-lineage-association--legacy,
-.task-lineage-association--ambiguous {
-  opacity: 0.78;
-}
-
-.task-lineage-association-main {
-  display: flex;
-  align-items: center;
-  gap: var(--space-sm);
-}
-
-.task-lineage-subject {
-  min-width: 0;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  white-space: nowrap;
-}
-
-.task-lineage-association-meta {
-  display: flex;
-  flex-wrap: wrap;
-  gap: var(--space-sm);
-  color: var(--text-muted);
-  font-size: 0.75rem;
-}
-
-.task-lineage-note {
-  margin: 0;
-  color: var(--text-dim);
-  font-size: 0.75rem;
-}
-
-@media (max-width: 768px) {
-  .task-lineage-associations-header {
-    flex-direction: column;
-    align-items: flex-start;
-  }
-
-  .task-lineage-association-main {
-    flex-wrap: wrap;
-  }
-
-  .task-lineage-subject {
-    white-space: normal;
-    overflow: visible;
-    text-overflow: clip;
-  }
-}

packages/dashboard/app/components/TaskChangesTab.tsx

@@ -4,9 +4,7 @@ import type { MergeDetails, Column } from "@fusion/core";
 import { getErrorMessage } from "@fusion/core";
 import {
   fetchTaskDiff,
-  fetchTaskCommitAssociations,
   type TaskDiff,
-  type TaskCommitAssociationRow,
 } from "../api";
 import { highlightDiff } from "../utils/highlightDiff";
 import { ChangesDiffModal } from "./ChangesDiffModal";
@@ -129,8 +127,6 @@ export function TaskChangesTab({ taskId, worktree, projectId, column, mergeDetai
   const [stats, setStats] = useState<{ filesChanged: number; additions: number; deletions: number }>({ filesChanged: 0, additions: 0, deletions: 0 });
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
-  const [commitAssociations, setCommitAssociations] = useState<TaskCommitAssociationRow[]>([]);
-  const [lineageId, setLineageId] = useState<string | null>(null);
   const [expandedFiles, setExpandedFiles] = useState<Set<string>>(new Set());
   const [currentFileIndex, setCurrentFileIndex] = useState<number | null>(null);
   const [wordWrap, setWordWrap] = useState(true);
@@ -150,9 +146,6 @@ export function TaskChangesTab({ taskId, worktree, projectId, column, mergeDetai
     try {
       setLoading(true);
       setError(null);
-      const associationsData = await fetchTaskCommitAssociations(taskId, projectId);
-      setLineageId(associationsData.lineageId);
-      setCommitAssociations(associationsData.associations);
 
       if (!canLoad) {
         setFiles([]);
@@ -261,47 +254,6 @@ export function TaskChangesTab({ taskId, worktree, projectId, column, mergeDetai
   }
 
 
-  const renderCommitAssociations = () => (
-    <section className="task-lineage-associations" aria-label="Task commit associations">
-      <div className="task-lineage-associations-header">
-        <h4>
-          <GitCommit size={16} />
-          Lineage commit associations
-        </h4>
-        {lineageId && (
-          <code className="task-lineage-id">{lineageId}</code>
-        )}
-      </div>
-      {commitAssociations.length === 0 ? (
-        <p className="task-lineage-associations-empty">No associated commits recorded yet.</p>
-      ) : (
-        <div className="task-lineage-associations-list">
-          {commitAssociations.map((association) => {
-            const matchedLabel = association.matchedBy.replace(/-/g, " ");
-            return (
-              <article
-                key={`${association.commitSha}-${association.matchedBy}`}
-                className={`task-lineage-association task-lineage-association--${association.confidence}`}
-              >
-                <div className="task-lineage-association-main">
-                  <code className="task-lineage-sha">{association.commitSha.slice(0, 7)}</code>
-                  <span className="task-lineage-subject">{association.commitSubject}</span>
-                </div>
-                <div className="task-lineage-association-meta">
-                  <span>{new Date(association.authoredAt).toLocaleString()}</span>
-                  <span>Confidence: {association.confidence}</span>
-                  <span>Match: {matchedLabel}</span>
-                  <span>Task snapshot: {association.taskIdSnapshot}</span>
-                </div>
-                {association.note && <p className="task-lineage-note">{association.note}</p>}
-              </article>
-            );
-          })}
-        </div>
-      )}
-    </section>
-  );
-
   if (files.length === 0) {
     if (isDone && !isDoneWithCommit) {
       const doneFallbackFiles = mergeDetails?.landedFiles && mergeDetails.landedFiles.length > 0
@@ -337,7 +289,6 @@ export function TaskChangesTab({ taskId, worktree, projectId, column, mergeDetai
 
     return (
       <div className="detail-section task-changes-tab">
-        {renderCommitAssociations()}
         <div className="task-changes-state task-changes-state--empty">
           <FileCode size={24} />
           <p>No files modified.</p>
@@ -353,7 +304,6 @@ export function TaskChangesTab({ taskId, worktree, projectId, column, mergeDetai
 
   return (
     <div className="detail-section task-changes-tab">
-      {renderCommitAssociations()}
       {/* Commit metadata for done tasks */}
       {isDone && mergeDetails && (
         <div className="commit-diff-meta">

packages/dashboard/app/components/__tests__/TaskCard-TaskChangesTab-parity.test.tsx

@@ -6,7 +6,6 @@ import { TaskChangesTab } from "../TaskChangesTab";
 
 const useTaskDiffStatsMock = vi.fn();
 const fetchTaskDiffMock = vi.fn();
-const fetchTaskCommitAssociationsMock = vi.fn();
 
 vi.mock("../../hooks/useTaskDiffStats", async (importOriginal) => {
   const actual = await importOriginal<typeof import("../../hooks/useTaskDiffStats")>();
@@ -21,7 +20,6 @@ vi.mock("../../api", async (importOriginal) => {
   return {
     ...actual,
     fetchTaskDiff: (...args: unknown[]) => fetchTaskDiffMock(...args),
-    fetchTaskCommitAssociations: (...args: unknown[]) => fetchTaskCommitAssociationsMock(...args),
   };
 });
 
@@ -83,8 +81,6 @@ describe("TaskCard/TaskChangesTab files-changed parity", () => {
   beforeEach(() => {
     useTaskDiffStatsMock.mockReset();
     fetchTaskDiffMock.mockReset();
-    fetchTaskCommitAssociationsMock.mockReset();
-    fetchTaskCommitAssociationsMock.mockResolvedValue({ taskId: "FN-4521", lineageId: null, associations: [] });
   });
 
   it.each([

packages/dashboard/app/components/__tests__/TaskChangesTab.test.tsx

@@ -5,11 +5,9 @@ import { TaskChangesTab } from "../TaskChangesTab";
 import type { MergeDetails, Column } from "@fusion/core";
 
 const mockFetchTaskDiff = vi.fn();
-const mockFetchTaskCommitAssociations = vi.fn();
 
 vi.mock("../../api", () => ({
   fetchTaskDiff: (...args: any[]) => mockFetchTaskDiff(...args),
-  fetchTaskCommitAssociations: (...args: any[]) => mockFetchTaskCommitAssociations(...args),
 }));
 
 vi.mock("lucide-react", () => ({
@@ -51,52 +49,6 @@ const MERGE_DETAILS: MergeDetails = {
 
 beforeEach(() => {
   mockFetchTaskDiff.mockReset();
-  mockFetchTaskCommitAssociations.mockReset();
-  mockFetchTaskCommitAssociations.mockResolvedValue({
-    taskId: "FN-001",
-    lineageId: "lineage-1",
-    associations: [],
-  });
-});
-
-describe("TaskChangesTab — commit associations", () => {
-  it("renders empty-state copy when no commit associations exist", async () => {
-    mockFetchTaskDiff.mockResolvedValue({ files: [], stats: { filesChanged: 0, additions: 0, deletions: 0 } });
-
-    render(<TaskChangesTab taskId="FN-001" worktree="/path/to/worktree" column="in-progress" />);
-
-    await waitFor(() => {
-      expect(screen.getByText("No associated commits recorded yet.")).toBeTruthy();
-    });
-  });
-
-  it("renders populated commit association rows with confidence metadata", async () => {
-    mockFetchTaskDiff.mockResolvedValue({ files: [], stats: { filesChanged: 0, additions: 0, deletions: 0 } });
-    mockFetchTaskCommitAssociations.mockResolvedValue({
-      taskId: "FN-001",
-      lineageId: "lineage-1",
-      associations: [
-        {
-          commitSha: "abc1234567",
-          commitSubject: "feat: lineage",
-          authoredAt: "2026-05-11T00:00:00.000Z",
-          matchedBy: "manual-reconciliation",
-          confidence: "ambiguous",
-          taskIdSnapshot: "FN-3953",
-          note: "legacy mismatch",
-        },
-      ],
-    });
-
-    const { container } = render(<TaskChangesTab taskId="FN-001" worktree="/path/to/worktree" column="in-progress" />);
-
-    await waitFor(() => {
-      expect(screen.getByText("feat: lineage")).toBeTruthy();
-    });
-    expect(screen.getByText("Confidence: ambiguous")).toBeTruthy();
-    expect(screen.getByText("Match: manual reconciliation")).toBeTruthy();
-    expect(container.querySelector(".task-lineage-association--ambiguous")).toBeTruthy();
-  });
 });
 
 describe("TaskChangesTab — worktree-backed (non-done tasks)", () => {