feat(pr-history): PR history view with proof snapshots (#572)

## Summary
- Backend: `GET /api/v2/pr/history` endpoint returning merged PRs with PROOF9 gate snapshots
- Backend: `pr_proof_snapshots` SQLite table capturing gate pass/fail at PR creation time
- Backend: `author` field on `PRDetails` dataclass from GitHub API
- Frontend: `PRHistoryPanel` component on Review page with expandable gate breakdown
- Tests: 11 Python tests + 13 Jest tests

## Validation
- Review feedback: All addressed (2 rounds — claude-review + CodeRabbit)
- Demo: All acceptance criteria verified via code review and test evidence
- Tests: All passing (Python 3158, Web-UI 773)
- CI: All checks green (both rounds)
- Linting: Clean

Closes #572

Author: frankbria

codeframe/core/proof/ledger.py

@@ -84,6 +84,18 @@ def init_proof_tables(workspace: Workspace) -> None:
         )
     """)
 
+    cursor.execute("""
+        CREATE TABLE IF NOT EXISTS pr_proof_snapshots (
+            pr_number INTEGER NOT NULL,
+            workspace_id TEXT NOT NULL,
+            gates_passed INTEGER NOT NULL,
+            gates_total INTEGER NOT NULL,
+            gate_breakdown TEXT NOT NULL,
+            snapshotted_at TEXT NOT NULL,
+            PRIMARY KEY (pr_number, workspace_id)
+        )
+    """)
+
     conn.commit()
     conn.close()
 
@@ -101,6 +113,11 @@ def _ensure_tables(workspace: Workspace) -> None:
             "SELECT name FROM sqlite_master WHERE type='table' AND name='proof_runs'"
         )
         missing = not cursor.fetchone()
+    if not missing:
+        cursor.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' AND name='pr_proof_snapshots'"
+        )
+        missing = not cursor.fetchone()
     conn.close()
     if missing:
         init_proof_tables(workspace)
@@ -493,3 +510,65 @@ def check_expired_waivers(workspace: Workspace) -> list[Requirement]:
         conn.commit()
     conn.close()
     return expired
+
+
+# --- PR Proof Snapshots ---
+
+
+def save_pr_proof_snapshot(
+    workspace: Workspace,
+    pr_number: int,
+    gates_passed: int,
+    gates_total: int,
+    gate_breakdown: list[dict],
+) -> None:
+    """Save a proof snapshot for a PR at creation time."""
+    _ensure_tables(workspace)
+    conn = get_db_connection(workspace)
+    cursor = conn.cursor()
+    cursor.execute(
+        """INSERT OR REPLACE INTO pr_proof_snapshots
+           (pr_number, workspace_id, gates_passed, gates_total,
+            gate_breakdown, snapshotted_at)
+           VALUES (?, ?, ?, ?, ?, ?)""",
+        (
+            pr_number,
+            workspace.id,
+            gates_passed,
+            gates_total,
+            json.dumps(gate_breakdown),
+            _utc_now().isoformat(),
+        ),
+    )
+    conn.commit()
+    conn.close()
+
+
+def get_pr_proof_snapshot(
+    workspace: Workspace, pr_number: int
+) -> Optional[dict]:
+    """Fetch a proof snapshot for a PR.
+
+    Returns:
+        Dict with pr_number, gates_passed, gates_total, gate_breakdown,
+        snapshotted_at — or None if not found.
+    """
+    _ensure_tables(workspace)
+    conn = get_db_connection(workspace)
+    cursor = conn.cursor()
+    cursor.execute(
+        """SELECT pr_number, gates_passed, gates_total, gate_breakdown, snapshotted_at
+           FROM pr_proof_snapshots WHERE pr_number = ? AND workspace_id = ?""",
+        (pr_number, workspace.id),
+    )
+    row = cursor.fetchone()
+    conn.close()
+    if not row:
+        return None
+    return {
+        "pr_number": row[0],
+        "gates_passed": row[1],
+        "gates_total": row[2],
+        "gate_breakdown": json.loads(row[3]),
+        "snapshotted_at": row[4],
+    }

codeframe/git/github_integration.py

@@ -54,6 +54,7 @@ class PRDetails:
     merged_at: Optional[datetime]
     head_branch: str
     base_branch: str
+    author: Optional[str] = None
 
 
 @dataclass
@@ -220,6 +221,9 @@ def _parse_pr_response(self, data: Dict[str, Any]) -> PRDetails:
                 data["merged_at"].replace("Z", "+00:00")
             )
 
+        user = data.get("user")
+        author = user.get("login") if isinstance(user, dict) else None
+
         return PRDetails(
             number=data["number"],
             url=data["html_url"],
@@ -230,6 +234,7 @@ def _parse_pr_response(self, data: Dict[str, Any]) -> PRDetails:
             merged_at=merged_at,
             head_branch=data["head"]["ref"],
             base_branch=data["base"]["ref"],
+            author=author,
         )
 
     async def create_pull_request(

codeframe/ui/routers/pr_v2.py

@@ -96,6 +96,39 @@ class PRStatusResponse(BaseModel):
     pr_number: int
 
 
+class GateBreakdownItem(BaseModel):
+    """A single gate pass/fail entry in a proof snapshot."""
+
+    gate: str
+    status: str
+
+
+class ProofSnapshotOut(BaseModel):
+    """Proof snapshot at time of PR creation."""
+
+    gates_passed: int
+    gates_total: int
+    gate_breakdown: list[GateBreakdownItem]
+
+
+class PRHistoryItem(BaseModel):
+    """A single merged PR with optional proof snapshot."""
+
+    number: int
+    title: str
+    merged_at: str
+    author: Optional[str]
+    url: str
+    proof_snapshot: Optional[ProofSnapshotOut]
+
+
+class PRHistoryResponse(BaseModel):
+    """Response for PR history list."""
+
+    pull_requests: list[PRHistoryItem]
+    total: int
+
+
 # ============================================================================
 # Helper Functions
 # ============================================================================
@@ -285,6 +318,78 @@ async def list_pull_requests(
         await client.close()
 
 
+@router.get("/history", response_model=PRHistoryResponse)
+@rate_limit_standard()
+async def get_pr_history(
+    request: Request,
+    limit: int = Query(10, ge=1, le=50),
+    workspace: Workspace = Depends(get_v2_workspace),
+) -> PRHistoryResponse:
+    """List recently merged PRs with proof snapshots.
+
+    Returns merged PRs sorted by merged_at descending, each with an
+    optional proof snapshot showing gate pass/fail at PR creation time.
+
+    Args:
+        limit: Maximum number of PRs to return (1-50, default 10)
+        workspace: v2 Workspace
+
+    Returns:
+        PRHistoryResponse with merged PRs and proof snapshots
+    """
+    from codeframe.core.proof.ledger import get_pr_proof_snapshot
+
+    client = _get_github_client()
+    try:
+        prs = await client.list_pull_requests(state="closed")
+
+        # Filter to only merged PRs and sort newest first.
+        merged = [pr for pr in prs if pr.merged_at is not None]
+        merged.sort(key=lambda pr: pr.merged_at, reverse=True)
+        merged = merged[:limit]
+
+        items: list[PRHistoryItem] = []
+        for pr in merged:
+            snapshot = get_pr_proof_snapshot(workspace, pr.number)
+            proof_snapshot = None
+            if snapshot:
+                proof_snapshot = ProofSnapshotOut(
+                    gates_passed=snapshot["gates_passed"],
+                    gates_total=snapshot["gates_total"],
+                    gate_breakdown=[
+                        GateBreakdownItem(**g) for g in snapshot["gate_breakdown"]
+                    ],
+                )
+            items.append(
+                PRHistoryItem(
+                    number=pr.number,
+                    title=pr.title,
+                    merged_at=pr.merged_at.isoformat(),
+                    author=pr.author,
+                    url=pr.url,
+                    proof_snapshot=proof_snapshot,
+                )
+            )
+
+        return PRHistoryResponse(pull_requests=items, total=len(items))
+
+    except GitHubAPIError as e:
+        raise HTTPException(
+            status_code=e.status_code,
+            detail=api_error("GitHub API error", ErrorCodes.EXECUTION_FAILED, e.message),
+        )
+    except HTTPException:
+        raise
+    except Exception as e:
+        logger.error(f"Failed to get PR history: {e}", exc_info=True)
+        raise HTTPException(
+            status_code=500,
+            detail=api_error("Failed to get PR history", ErrorCodes.EXECUTION_FAILED, str(e)),
+        )
+    finally:
+        await client.close()
+
+
 @router.get("/{pr_number}", response_model=PRResponse)
 @rate_limit_standard()
 async def get_pull_request(
@@ -355,6 +460,41 @@ async def create_pull_request(
             base=body.base,
         )
 
+        # Capture proof snapshot at PR creation time.
+        try:
+            from codeframe.core.proof.ledger import (
+                init_proof_tables,
+                list_requirements,
+                save_pr_proof_snapshot,
+            )
+
+            init_proof_tables(workspace)
+            reqs = list_requirements(workspace)
+
+            gates_total = 0
+            gates_passed = 0
+            gate_breakdown: list[dict] = []
+            for req in reqs:
+                for ob in req.obligations:
+                    gates_total += 1
+                    passed = ob.status == "satisfied"
+                    if passed:
+                        gates_passed += 1
+                    gate_breakdown.append({
+                        "gate": ob.gate.value,
+                        "status": ob.status,
+                    })
+
+            save_pr_proof_snapshot(
+                workspace,
+                pr_number=pr.number,
+                gates_passed=gates_passed,
+                gates_total=gates_total,
+                gate_breakdown=gate_breakdown,
+            )
+        except Exception as snap_err:
+            logger.warning(f"Failed to save proof snapshot for PR #{pr.number}: {snap_err}")
+
         return _pr_to_response(pr)
 
     except GitHubAPIError as e:

tests/core/test_proof_snapshot.py

@@ -0,0 +1,110 @@
+"""Tests for pr_proof_snapshots ledger functions.
+
+Verifies save_pr_proof_snapshot and get_pr_proof_snapshot work correctly
+with the SQLite-backed proof ledger.
+"""
+
+import shutil
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from codeframe.core.workspace import create_or_load_workspace
+
+pytestmark = pytest.mark.v2
+
+
+@pytest.fixture
+def test_workspace():
+    temp_dir = Path(tempfile.mkdtemp())
+    workspace_path = temp_dir / "test_ws"
+    workspace_path.mkdir(parents=True, exist_ok=True)
+
+    workspace = create_or_load_workspace(workspace_path)
+
+    yield workspace
+
+    shutil.rmtree(temp_dir, ignore_errors=True)
+
+
+class TestPrProofSnapshot:
+    """Tests for save/get pr_proof_snapshot functions."""
+
+    def test_save_and_get_snapshot(self, test_workspace):
+        """Save a snapshot, retrieve it, verify all fields."""
+        from codeframe.core.proof.ledger import (
+            init_proof_tables,
+            save_pr_proof_snapshot,
+            get_pr_proof_snapshot,
+        )
+
+        init_proof_tables(test_workspace)
+
+        gate_breakdown = [
+            {"gate": "unit_test", "status": "satisfied"},
+            {"gate": "lint", "status": "failed"},
+        ]
+        save_pr_proof_snapshot(
+            test_workspace,
+            pr_number=42,
+            gates_passed=1,
+            gates_total=2,
+            gate_breakdown=gate_breakdown,
+        )
+
+        result = get_pr_proof_snapshot(test_workspace, 42)
+
+        assert result is not None
+        assert result["pr_number"] == 42
+        assert result["gates_passed"] == 1
+        assert result["gates_total"] == 2
+        assert result["gate_breakdown"] == gate_breakdown
+        assert "snapshotted_at" in result
+
+    def test_get_nonexistent_snapshot_returns_none(self, test_workspace):
+        """Getting a snapshot for a non-existent PR returns None."""
+        from codeframe.core.proof.ledger import (
+            init_proof_tables,
+            get_pr_proof_snapshot,
+        )
+
+        init_proof_tables(test_workspace)
+
+        result = get_pr_proof_snapshot(test_workspace, 9999)
+        assert result is None
+
+    def test_snapshot_overwrites_on_same_pr_number(self, test_workspace):
+        """Saving a snapshot for the same PR overwrites the previous one."""
+        from codeframe.core.proof.ledger import (
+            init_proof_tables,
+            save_pr_proof_snapshot,
+            get_pr_proof_snapshot,
+        )
+
+        init_proof_tables(test_workspace)
+
+        save_pr_proof_snapshot(
+            test_workspace,
+            pr_number=10,
+            gates_passed=3,
+            gates_total=5,
+            gate_breakdown=[{"gate": "unit_test", "status": "satisfied"}],
+        )
+
+        save_pr_proof_snapshot(
+            test_workspace,
+            pr_number=10,
+            gates_passed=5,
+            gates_total=5,
+            gate_breakdown=[
+                {"gate": "unit_test", "status": "satisfied"},
+                {"gate": "lint", "status": "satisfied"},
+            ],
+        )
+
+        result = get_pr_proof_snapshot(test_workspace, 10)
+        assert result is not None
+        assert result["gates_passed"] == 5
+        assert result["gates_total"] == 5
+        assert len(result["gate_breakdown"]) == 2