Description:
The emulate_cpu tool located in src/tools/emulation.ts does not currently support disabling CPU emulation once it has been enabled. The throttlingRate parameter enforces a minimum value of 1, which applies the lowest level of throttling but does not fully disable the emulation. This behavior is inconsistent with the emulate_network tool, which allows network emulation to be completely turned off.

The underlying Puppeteer API (page.emulateCPUThrottling) expects a value of null or 0 to disable CPU throttling, which is not supported by the current implementation.

To Reproduce:

1. Enable CPU emulation using the emulate_cpu tool.
2. Try setting throttlingRate = 0 or attempt to disable the feature.
3. Observe that throttling remains active at the minimum level instead of turning off.
4. Compare this behavior with emulate_network, which allows disabling.

Expected Behavior:
Setting throttlingRate to 0 or null should fully disable CPU emulation, in line with how emulate_network behaves. The tool should allow disabling the feature entirely without requiring a full reload.