fix(P03): improve planner task descriptions — avoid redundant REQ-ID in task lines

---ci---
phase: 3
milestone: v0.6.0
plan: 03
task: 03-03
status: execute
---/ci---

src/agents/planner.ts

@@ -222,7 +222,10 @@ export class PlannerAgent extends BaseAgent {
           wave: 1,
           requirements: chunk.map((r) => r.id),
           dependsOn: [],
-          tasks: chunk.map((r) => `Implement ${r.id}: ${r.description.split(": ").slice(1).join(": ") || r.description}`),
+          tasks: chunk.map((r) => {
+            const desc = r.description.split(": ").slice(1).join(": ") || r.description;
+            return desc !== r.id ? `Implement ${r.id}: ${desc}` : `Implement ${r.id}`;
+          }),
           mustHaves: chunk.map((r) => `${r.id} implemented and testable`),
         });
       }
@@ -236,7 +239,10 @@ export class PlannerAgent extends BaseAgent {
           wave: plans.length > 0 ? Math.max(...plans.map((p) => p.wave)) + 1 : 2,
           requirements: chunk.map((r) => r.id),
           dependsOn: plans.slice(0, plans.length > 0 ? 1 : 0).map((p) => p.name),
-          tasks: chunk.map((r) => `Implement ${r.id}: ${r.description.split(": ").slice(1).join(": ") || r.description}`),
+          tasks: chunk.map((r) => {
+            const desc = r.description.split(": ").slice(1).join(": ") || r.description;
+            return desc !== r.id ? `Implement ${r.id}: ${desc}` : `Implement ${r.id}`;
+          }),
           mustHaves: chunk.map((r) => `${r.id} implemented and testable`),
         });
       }