fix: Convert priority enum values to strings for Gemini API compatibility

- Change priority enum from [1, 2, 3, 4, null] to ["1", "2", "3", "4", null]
- Update type from 'number' to 'string' in update_task and update_bulk_tasks tools
- Fixes Cursor IDE and Gemini CLI compatibility issues (closes #79)
- Maintains backward compatibility via existing toTaskPriority() function

The Gemini API expects enum values as strings, while the previous numeric
enum values were causing schema validation errors in Gemini-based MCP clients.

Author: taazkareem

src/tools/task/bulk-operations.ts

@@ -226,9 +226,9 @@ export const updateBulkTasksTool = {
               description: "New status"
             },
             priority: {
-              type: "number",
+              type: "string",
               nullable: true,
-              enum: [1, 2, 3, 4, null],
+              enum: ["1", "2", "3", "4", null],
               description: "New priority (1-4 or null)"
             },
             dueDate: {

src/tools/task/single-operations.ts

@@ -197,9 +197,9 @@ export const updateTaskTool = {
         description: "New status. Must be valid for the task's current list."
       },
       priority: {
-        type: "number",
+        type: "string",
         nullable: true,
-        enum: [1, 2, 3, 4, null],
+        enum: ["1", "2", "3", "4", null],
         description: "New priority: 1 (urgent) to 4 (low). Set null to clear priority."
       },
       dueDate: {