feat(plane-lift): API routes, UI components, migrations — Phase 2

New API routes:
- statuses.ts: CRUD for custom task statuses
- automations.ts: automation rules engine
- timeline.ts: entity timeline/activity view
- activity.ts: activity feed endpoint

New UI components:
- gantt/: gantt chart (6 files: chart, task-bar, milestone, timeline, deps, utils)
- automation-rule-builder.tsx: visual rule editor
- notification-center.tsx: in-app notifications
- quick-add-bar.tsx: global quick-add
- entities/: detail-page, activity, comments, inline-edit, note-editor
- tasks/: recurrence-picker

New hooks:
- use-optimistic-patch.ts: optimistic UI updates

New libs:
- nlp-parser.ts + test: natural language task parsing
- notify.ts: notification dispatch
- automation-engine.ts: rule evaluation

DB migrations:
- 0007_custom_task_statuses.sql
- 0008_automation_rules.sql
- 0009_notifications.sql
- migrate-task-statuses.ts: backfill script

Modified:
- tasks.ts: plane-lift integration (stateId/moduleId/cycleId)
- analytics.ts: updated for new schema
- canvas/$id.tsx: restored

apps/web/src/components/gantt/gantt-dependency-arrow.tsx

@@ -0,0 +1,50 @@
+import type { TimelineTask } from "./gantt-utils";
+
+export interface TaskPosition {
+  /** Left edge of the task's bar in timeline pixels. */
+  startX: number;
+  /** Right edge of the task's bar in timeline pixels. */
+  endX: number;
+  /** Vertical center of the task's row in pixels. */
+  y: number;
+}
+
+interface GanttDependencyArrowProps {
+  /** The task being depended on (arrow originates at the end of its bar). */
+  fromTask: TimelineTask;
+  /** The blocked task (arrowhead lands at the start of its bar). */
+  toTask: TimelineTask;
+  taskPositions: ReadonlyMap<string, TaskPosition>;
+}
+
+const BEND = 12;
+
+/**
+ * SVG elbow arrow from the end of the blocking task's bar to the start of the
+ * blocked task's bar. Rendered inside the chart's overlay <svg> — the marker
+ * is defined there under the id `gantt-arrow`.
+ */
+export function GanttDependencyArrow({ fromTask, toTask, taskPositions }: GanttDependencyArrowProps) {
+  const from = taskPositions.get(fromTask.id);
+  const to = taskPositions.get(toTask.id);
+  if (!from || !to) return null;
+
+  const x1 = from.endX;
+  const y1 = from.y;
+  // If the target bar starts before the source ends, drop the arrowhead just
+  // past the source end so the elbow path never doubles back on itself.
+  const x2 = Math.max(to.startX, from.endX + BEND);
+  const y2 = to.y;
+  const d = `M ${x1} ${y1} H ${x1 + BEND} L ${x2 - BEND} ${y2} H ${x2}`;
+
+  return (
+    <path
+      d={d}
+      fill="none"
+      stroke="currentColor"
+      strokeWidth={1.5}
+      markerEnd="url(#gantt-arrow)"
+      className="text-muted-foreground/70"
+    />
+  );
+}