perf(monitor): keep refresh work compact and observable

docs/observability.md

@@ -78,6 +78,35 @@ series; size your collector/Prometheus retention accordingly.
 The metric-name constants are the single source of truth in
 `rust/crates/aetower-telemetry/src/lib.rs` (`pub mod metric_names`).
 
+## Local UI refresh diagnostics
+
+Aetower emits a bounded `ui-refresh-slow` diagnostic when a UI refresh takes at
+least 250 ms or publication takes at least 120 ms, and a periodic
+`ui-refresh-sample` for the intervening refreshes. The sample window records its
+actual `window_duration_millis` and `window_refreshes`; counts include updated,
+no-change, failed, and cancelled cycles, so a slow-event count can be compared
+with the observed denominator.
+
+Per-refresh timings include `full_snapshot_fetch_millis`,
+`evaluator_snapshot_fetch_millis`, `monitor_payload_fetch_millis`,
+`runtime_lag_fetch_millis`, `operator_state_fetch_millis`,
+`worker_total_millis`, `monitor_decode_millis`, `monitor_row_build_millis`,
+`publish_millis`, and `ui_refresh_millis`. Window `*_fetches` and
+`window_worker_total_attempts` count attempts; their `*_timing_samples` fields
+(and `window_worker_samples`) count only calls with measured durations. Means
+use timing-sample counts, not attempt counts; when no samples exist, the mean is
+`n/a`. An attempted call that throws therefore increments its attempt counter; its
+elapsed time is recorded when measurable, otherwise it contributes no fabricated
+zero to the mean. Per-refresh phase durations are `n/a` when unavailable, and
+`bridge_call_total_millis` is `n/a` if any attempted Bridge phase lacks a
+duration.
+
+The existing runtime metric `bridge_fetch_millis` deliberately retains its
+original scope: it measures only the full `SystemSnapshot` fetch. It does not
+include the compact Monitor delta, runtime-lag metrics, operator-state Bridge
+calls, or total refresh time. Use the local per-phase event fields to compare
+those costs; do not interpret `bridge_fetch_millis` as the whole Bridge path.
+
 ## Collector + Prometheus setup
 
 Minimal `otel-collector-config.yaml` that receives OTLP/HTTP from Aetower and

macos/Sources/AetowerApp/AetowerApp.swift

@@ -1137,7 +1137,6 @@ struct AetowerApp: App {
         WindowGroup {
             TabView(selection: $nav.workspace) {
                 MainListView(state: state, settings: settings)
-                    .demandsFullSnapshot(from: state, reason: "monitor")
                     .tabItem {
                         Label(WorkspaceTab.monitor.title, systemImage: WorkspaceTab.monitor.systemImage)
                     }

macos/Sources/AetowerBindings/aetower_ffi.swift

@@ -7653,6 +7653,7 @@ public struct UiHostSummary {
     public var gpuPercent: Float
     public var gpuMemoryBytes: UInt64
     public var thermalState: ThermalState
+    public var thermalForecast: ThermalForecast?
     public var onBattery: Bool
     public var lowPowerMode: Bool
     public var frontmostAppName: String?
@@ -7663,7 +7664,7 @@ public struct UiHostSummary {
 
     // Default memberwise initializers are never public by default, so we
     // declare one manually.
-    public init(machineFriction: Float, cpuPercent: Float, memoryUsedBytes: UInt64, memoryTotalBytes: UInt64, compressedMemoryBytes: UInt64, swapUsedBytes: UInt64, diskReadBps: UInt64, diskWriteBps: UInt64, networkReceiveBps: UInt64, networkSendBps: UInt64, wakeupsPerSecond: Float, gpuPercent: Float, gpuMemoryBytes: UInt64, thermalState: ThermalState, onBattery: Bool, lowPowerMode: Bool, frontmostAppName: String?, frontmostWindowTitle: String?, aiAgentCount: UInt32, entityCount: UInt32, processCount: UInt32) {
+    public init(machineFriction: Float, cpuPercent: Float, memoryUsedBytes: UInt64, memoryTotalBytes: UInt64, compressedMemoryBytes: UInt64, swapUsedBytes: UInt64, diskReadBps: UInt64, diskWriteBps: UInt64, networkReceiveBps: UInt64, networkSendBps: UInt64, wakeupsPerSecond: Float, gpuPercent: Float, gpuMemoryBytes: UInt64, thermalState: ThermalState, thermalForecast: ThermalForecast?, onBattery: Bool, lowPowerMode: Bool, frontmostAppName: String?, frontmostWindowTitle: String?, aiAgentCount: UInt32, entityCount: UInt32, processCount: UInt32) {
         self.machineFriction = machineFriction
         self.cpuPercent = cpuPercent
         self.memoryUsedBytes = memoryUsedBytes
@@ -7678,6 +7679,7 @@ public struct UiHostSummary {
         self.gpuPercent = gpuPercent
         self.gpuMemoryBytes = gpuMemoryBytes
         self.thermalState = thermalState
+        self.thermalForecast = thermalForecast
         self.onBattery = onBattery
         self.lowPowerMode = lowPowerMode
         self.frontmostAppName = frontmostAppName
@@ -7737,6 +7739,9 @@ extension UiHostSummary: Equatable, Hashable {
         if lhs.thermalState != rhs.thermalState {
             return false
         }
+        if lhs.thermalForecast != rhs.thermalForecast {
+            return false
+        }
         if lhs.onBattery != rhs.onBattery {
             return false
         }
@@ -7776,6 +7781,7 @@ extension UiHostSummary: Equatable, Hashable {
         hasher.combine(gpuPercent)
         hasher.combine(gpuMemoryBytes)
         hasher.combine(thermalState)
+        hasher.combine(thermalForecast)
         hasher.combine(onBattery)
         hasher.combine(lowPowerMode)
         hasher.combine(frontmostAppName)
@@ -7809,6 +7815,7 @@ public struct FfiConverterTypeUiHostSummary: FfiConverterRustBuffer {
                 gpuPercent: FfiConverterFloat.read(from: &buf),
                 gpuMemoryBytes: FfiConverterUInt64.read(from: &buf),
                 thermalState: FfiConverterTypeThermalState.read(from: &buf),
+                thermalForecast: FfiConverterOptionTypeThermalForecast.read(from: &buf),
                 onBattery: FfiConverterBool.read(from: &buf),
                 lowPowerMode: FfiConverterBool.read(from: &buf),
                 frontmostAppName: FfiConverterOptionString.read(from: &buf),
@@ -7834,6 +7841,7 @@ public struct FfiConverterTypeUiHostSummary: FfiConverterRustBuffer {
         FfiConverterFloat.write(value.gpuPercent, into: &buf)
         FfiConverterUInt64.write(value.gpuMemoryBytes, into: &buf)
         FfiConverterTypeThermalState.write(value.thermalState, into: &buf)
+        FfiConverterOptionTypeThermalForecast.write(value.thermalForecast, into: &buf)
         FfiConverterBool.write(value.onBattery, into: &buf)
         FfiConverterBool.write(value.lowPowerMode, into: &buf)
         FfiConverterOptionString.write(value.frontmostAppName, into: &buf)