Fix all 8 audit issues from unified threshold review

Medium: start() no longer bypasses curve for Max — tick() handles
all profiles through proportional curves and sustained trigger.

Low: removed dead alwaysOn code from switchProfile(), selectProfile(),
and the convenience initializer. Fixed stale default startTemp (60→55).

High: README Smart documentation corrected — 53-85°C range (was 60-85),
hysteresis 53/50 with 3°C gap (was 60/55 with 5°C gap).

Author: Producer Guy

README.md

@@ -127,7 +127,7 @@ Apple doesn't do this because silence sells in store demos and most users never
 
 ### How Smart works
 
-**The curve:** Smart maps temperature to fan speed across a 60–85°C range. Below 60°C, fans stay off. Above 85°C, fans go to max. Between those points, fan speed scales proportionally using an S-curve (gentle at low temps, steeper approaching the ceiling).
+**The curve:** Smart maps temperature to fan speed across a 53–85°C range. Below 50°C, fans turn off. Between 50–53°C, fans maintain current state (hysteresis). Above 85°C, fans go to max. Between those points, fan speed scales proportionally using an S-curve (gentle at low temps, steeper approaching the ceiling).
 
 **Rate-of-change awareness:** Smart doesn't just look at where temperature is — it looks at how fast it's moving. If temp is rising at 1°C/sec, Smart boosts fan speed proportionally to get ahead of the climb. If temp is stable or falling, Smart holds steady or eases off gradually.
 
@@ -137,7 +137,7 @@ Apple doesn't do this because silence sells in store demos and most users never
 
 **Ramp governors:** Fan speed changes are rate-limited to match Apple's hardware behavior. Ramp up at ~400 RPM/sec, ramp down at ~200 RPM/sec. This prevents acoustic shock, reduces mechanical stress, and extends fan bearing lifespan by up to 50% compared to abrupt speed changes (source: [NMB fan engineering](https://nmbtc.com/white-papers/dc-brushless-cooling-fan-behavior/), [Analog Devices ADM1031 datasheet](https://www.onsemi.com/download/data-sheet/pdf/adm1031-d.pdf)).
 
-**Hysteresis:** Fans turn on at 60°C and turn off at 55°C — a 5°C gap. This prevents rapid on/off cycling, which is the #1 cause of fan bearing wear in fluid dynamic bearing fans (source: [Nidec FDB technology](https://www.nidec.com/en/technology/capability/fdb/), [AnandTech fan lifespan discussion](https://forums.anandtech.com/threads/fan-stop-start-effect-on-lifespan.2284098/)).
+**Hysteresis:** Fans turn on at 53°C (after 8 seconds sustained) and turn off at 50°C — a 3°C gap. All other profiles use 55°C start with a 5°C gap. This prevents rapid on/off cycling, which is the #1 cause of fan bearing wear in fluid dynamic bearing fans (source: [Nidec FDB technology](https://www.nidec.com/en/technology/capability/fdb/), [AnandTech fan lifespan discussion](https://forums.anandtech.com/threads/fan-stop-start-effect-on-lifespan.2284098/)).
 
 **0 to minimum RPM is binary:** Apple Silicon MacBook fans cannot spin below their minimum RPM (2317 on M5 Max, 1200 on M1 Max). When Smart decides fans should run, they jump directly to minimum — this is a hardware limitation of brushless DC motors that require a startup burst to overcome static friction. Above minimum, all speed changes are smooth and governed.
 

Sources/ThermalForgeApp/AppState.swift

@@ -124,17 +124,14 @@ final class AppState: ObservableObject {
         monitor?.switchProfile(profile)
         TFLogger.shared.profile("Selected: \(profile.name)")
 
-        // Only Max applies fans immediately — all other profiles
-        // are handled by tick() curve evaluation each cycle
+        // All profiles use proportional curves — tick() handles fan engagement.
+        // Reset to auto on profile change so tick() starts from a clean state.
         do {
-            if profile.curve.alwaysOn {
-                try executor.execute(.setMax)
-            } else if profile.curve.handsOff || profile.id == "smart" {
-                // Silent and Smart: tick() handles it, reset to auto first
+            if profile.curve.handsOff || profile.id == "smart" || profile.id == "silent" {
                 try executor.execute(.resetAuto)
             }
-            // Balanced/Performance: tick() will ramp proportionally
-            // based on current temperature — no immediate fan command
+            // Balanced/Performance/Max: tick() will ramp proportionally
+            // based on current temperature after sustained trigger is met
         } catch {
             TFLogger.shared.error("Profile \(profile.name) failed: \(error)")
         }

Sources/ThermalForgeCore/Profile.swift

@@ -44,7 +44,7 @@ public struct FanProfile: Codable, Identifiable, Equatable {
         /// If true, fans are always at maxRPMPercent regardless of temperature.
         public let alwaysOn: Bool
 
-        public init(stopTemp: Float = 50, startTemp: Float = 60, ceilingTemp: Float = 70,
+        public init(stopTemp: Float = 50, startTemp: Float = 55, ceilingTemp: Float = 70,
                     maxRPMPercent: Float = 0.6, handsOff: Bool = false, alwaysOn: Bool = false) {
             self.stopTemp = stopTemp
             self.startTemp = startTemp
@@ -209,16 +209,3 @@ extension FanProfile {
     public static let hysteresisDegrees: Float = 5.0
 }
 
-// MARK: - Curve Initializer Convenience
-
-extension FanProfile.Curve {
-    /// Convenience for always-on profiles (Max)
-    public init(alwaysOn: Bool, maxRPMPercent: Float) {
-        self.stopTemp = 0
-        self.startTemp = 0
-        self.ceilingTemp = 0
-        self.maxRPMPercent = maxRPMPercent
-        self.handsOff = false
-        self.alwaysOn = alwaysOn
-    }
-}

Sources/ThermalForgeCore/ThermalMonitor.swift

@@ -94,11 +94,7 @@ public final class ThermalMonitor {
     public func start(interval: TimeInterval = 2.0) {
         stop()
 
-        // If profile is Max, apply immediately
-        if activeProfile.id == "max" {
-            applyCommand(.setMax)
-            state = .active(profileName: "Max")
-        }
+        // All profiles use proportional curves now — tick() handles engagement
 
         let timer = DispatchSource.makeTimerSource(queue: queue)
         timer.schedule(deadline: .now(), repeating: interval)
@@ -134,11 +130,7 @@ public final class ThermalMonitor {
                 }
             }
 
-            if profile.curve.alwaysOn {
-                state = .active(profileName: profile.name)
-            } else {
-                state = .idle
-            }
+            state = .idle
         }
     }