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.

frontend/src/components/Profiles/ProfilePanel.tsx

@@ -345,6 +345,11 @@ export function ProfilePanel({
                           {badges && (
                             <p className="text-xs text-zinc-500">{badges}</p>
                           )}
+                          {p.power_cap_mode === "ioctl" && (
+                            <p className="text-xs text-red-400 font-medium">
+                              ⚠ experimental power (below VBIOS min)
+                            </p>
+                          )}
                         </div>
                       </div>