fix: add missing items definition to labelIds array schema

The plan_update_issue tool schema defined labelIds as type "array"
without an items definition, causing HTTP 400 from the LLM API on
every session that loaded planner tools — including unrelated cron jobs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: calltelemetry-jason

src/tools/planner-tools.ts

@@ -408,6 +408,7 @@ export function createPlannerTools(): AnyAgentTool[] {
           priority: { type: "number", description: "New priority: 1=Urgent, 2=High, 3=Medium, 4=Low" },
           labelIds: {
             type: "array",
+            items: { type: "string" },
             description: "Label IDs to set",
           },
         },