macbook: raise mbpfan thresholds so the fan stays quiet at idle

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

hosts/FredOS-Macbook.nix

@@ -35,13 +35,14 @@
     # The SMC holds the fan at its 1200 RPM floor while the package sits at
     # 79C — measured 1210 RPM at settled idle. (An earlier 5813 RPM reading
     # was a rebuild spinning down, not the steady state.) Nothing in-tree
-    # ramps applesmc, so drive it directly and start well before 79C.
+    # ramps applesmc, so drive it directly. Tjmax is 100C and thermald throttles
+    # long before that, so no reason for the fan to leave its floor in the 60s.
     services.mbpfan = {
       enable = true;
       settings.general = {
-        low_temp = 55;   # below this, coast at minimum
-        high_temp = 65;  # start climbing here
-        max_temp = 80;   # full tilt — the old ceiling was above idle temp
+        low_temp = 68;   # below this, coast at minimum
+        high_temp = 80;  # start climbing here
+        max_temp = 92;   # full tilt, still 8C under Tjmax
       };
     };