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/Limits/PerformancePanel.tsx

@@ -72,6 +72,21 @@ export function PerformancePanel() {
     }
   }
 
+  async function handleModeChange(enabled: boolean) {
+    setBusy(true);
+    try {
+      await api.updateLimits(
+        { power_cap_mode: enabled ? "ioctl" : "nvml" },
+        selectedGpuIndex,
+      );
+      await fetchLimits();
+    } catch (e: unknown) {
+      toast.error(e instanceof Error ? e.message : String(e));
+    } finally {
+      setBusy(false);
+    }
+  }
+
   if (loading && !limits) {
     return (
       <div className="bg-zinc-900 rounded-lg overflow-hidden flex flex-col animate-pulse">
@@ -158,12 +173,80 @@ export function PerformancePanel() {
         )}
 
         <div className="flex flex-col divide-y divide-zinc-800">
+          {/* ── Experimental NVIDIA power control ─────────────────────────── */}
+          {(limits.rm_power_supported || limits.power_cap_mode === "ioctl") && (
+            <div className="px-4 py-3 flex flex-col gap-2">
+              <label className="flex items-center gap-2 cursor-pointer select-none">
+                <input
+                  type="checkbox"
+                  checked={limits.power_cap_mode === "ioctl"}
+                  disabled={busy}
+                  onChange={(e) => handleModeChange(e.target.checked)}
+                  className="accent-red-500"
+                />
+                <span className="text-xs text-zinc-300">
+                  Experimental NVIDIA power control
+                </span>
+              </label>
+              {limits.rm_power_supported ? (
+                <div
+                  role="alert"
+                  className={
+                    "px-2.5 py-1.5 rounded border text-xs leading-relaxed " +
+                    (limits.power_cap_mode === "ioctl"
+                      ? "bg-red-950/80 border-red-500 text-red-300"
+                      : "bg-red-950/40 border-red-800 text-red-400")
+                  }
+                >
+                  <span className="font-bold">⚠ WARNING:</span> uses an
+                  undocumented driver interface for ALL power limits, including
+                  resets. Allows values below the VBIOS minimum (down to 30 W)
+                  and may cause instability or stop working after driver
+                  updates. Enable at your own risk. Based on the work of{" "}
+                  <a
+                    href="https://github.com/ilya-zlobintsev/LACT/pull/1205"
+                    target="_blank"
+                    rel="noopener noreferrer"
+                    className="underline hover:text-red-200"
+                  >
+                    panchovix
+                  </a>{" "}
+                  (LACT PR #1205).
+                </div>
+              ) : (
+                <div
+                  role="alert"
+                  className="px-2.5 py-1.5 rounded border border-red-500 bg-red-950/80 text-red-300 text-xs leading-relaxed"
+                >
+                  <span className="font-bold">
+                    ⚠ Interface not currently available.
+                  </span>
+                  The driver no longer exposes the RM power interface (it may
+                  have been updated). Experimental mode is still enabled, so
+                  power-limit changes will fail. Uncheck to switch back to the
+                  standard NVML mode.
+                </div>
+              )}
+            </div>
+          )}
+
           {/* ── Board Power Limit ─────────────────────────────────────────── */}
           <div className="px-4 py-4 flex flex-col gap-3">
             <div className="flex items-center justify-between">
-              <span className="text-xs text-zinc-500 uppercase tracking-wider">
-                Board Power Limit
-              </span>
+              <div className="flex items-center gap-2">
+                <span className="text-xs text-zinc-500 uppercase tracking-wider">
+                  Board Power Limit
+                </span>
+                {limits.power_cap_mode === "ioctl" &&
+                  limits.min_power_limit_w_native != null && (
+                    <span
+                      className="text-xs text-red-400/80 font-mono"
+                      title="Native VBIOS minimum — experimental mode allows lower"
+                    >
+                      VBIOS min {limits.min_power_limit_w_native} W
+                    </span>
+                  )}
+              </div>
               <div className="flex items-center gap-1.5">
                 <input
                   type="number"