feat: experimental NVIDIA power control via RM ioctl interface

Adds an experimental power-cap mode using the undocumented RM ioctl
interface (based on panchovix's LACT PR #1205) to set power limits
below the VBIOS minimum (down to 30 W).

- hal/rm_power.py: RM ioctl power-cap read/write/reset + runtime probe
- limits.py: power_cap_mode (nvml/ioctl) with support detection
- config.py: persist power_cap_mode per GPU
- profiles: record/apply power_cap_mode
- server.py: POST /api/limits validates ioctl support (409 on failure)
- cli.py: profile save falls back to persisted mode
- client.py: power_cap_mode in Limits
- frontend: toggle + warning with panchovix attribution (LACT #1205)
- tests: test_rm_power.py (unit) + integration coverage
- Makefile: add test_rm_power.py to make test

Also includes automated linter reformatting (prettier, ruff, shellcheck,
isort, markdownlint) that the linter would apply anyway.

Makefile

@@ -24,6 +24,7 @@ dev: ## Create/refresh the dev environment (uv sync)
 
 test: ## Run the test suite
 	$(UV) run python tests/test_security.py
+	$(UV) run python tests/test_rm_power.py
 
 clean: ## Remove build artifacts
 	rm -rf frontend/dist frontend/node_modules