feat(dareu): add A950 PRO Mg support - #78

Summary

• Add the Dareu Jm codec and WebHID driver for the A950 PRO Mg.
• Register receiver VID/PID 260D:1114 and direct mouse PID 1117, gated by the measured 16-byte report-8 command collection.
• Add protocol, driver, and hardware-path verification tests.
• Document the packet format, evidence, and unsupported command boundary.

Hardware verification

• Device: Dareu A950 PRO Mg (TM271F)
• Verified connection:
  • 2.4 GHz receiver (260D:1114)
• Recognized but not hardware-verified:
  • Wired mouse (1117)

Tested functionality

• Receiver discovery and status reads
• Battery and firmware reads
• DPI stages and polling-rate commands with read-back
• Mouse and DPI-indicator sleep commands with read-back
• DPI-indicator effect, brightness, and speed command ordering
• Profile selection and safe button mappings
• Unknown or macro button records remain read-only

Verification

• npm run build
• npx tsx --test src/dareu/index.test.ts src/drivers/dareu/hid.test.ts (12/12)
• git diff --check

Notes

The driver intentionally covers only the A950 PRO Mg. It does not issue reset, calibration, firmware, pairing, or macro-write commands. The repository-wide npm run check remains blocked by an unrelated existing MCHOSE test worker that does not terminate; the focused Dareu suite passes.