fix(esmole): truncate all tool responses; guard normalizes leading slash

packages/esmole-mcp/test/unit/tools/mapping.test.ts

@@ -28,4 +28,26 @@ describe('runGetMapping', () => {
         expect(out.body).toEqual({ error: 'not_found' })
         expect(out.fields).toBeUndefined()
     })
+    it('truncates an over-budget flattened-fields response', async () => {
+        const properties: Record<string, { type: string }> = {}
+        for (let i = 0; i < 50; i++) {
+            properties['field_with_a_long_name_' + i] = { type: 'keyword' }
+        }
+        const out = await runGetMapping(
+            managed(200, { idx: { mappings: { properties } } }),
+            'idx',
+            false,
+            100
+        )
+        expect(out.truncated).toBe(true)
+    })
+    it('truncates an over-budget raw response', async () => {
+        const big: Record<string, string> = {}
+        for (let i = 0; i < 50; i++) {
+            big['key_with_a_fairly_long_name_' + i] = 'some value here ' + i
+        }
+        const out = await runGetMapping(managed(200, big), 'idx', true, 100)
+        expect(out.truncated).toBe(true)
+        expect(out.fields).toBeUndefined()
+    })
 })