feat(core,clients): one rumble policy engine for every platform (rumble root fix D)

punktfunk-core client/rumble.rs: a per-connection policy engine consumes seq-gated wire
updates and emits EFFECTIVE actuator commands — re-emits on renewals (duration APIs stay
re-armed), self-silences at the v2 lease, a UNIFORM 1 s legacy-host staleness replacing the
per-platform zoo (Apple 1.6 s / Android 60 s / SDL 1.5 s / Deck 1 s), quirk-declared
actuator keepalives (Deck 40 ms + LSB dedupe-defeat jitter), and one stop per buzzing pad
on connection close. Per-pad mailbox semantics: a stalled embedder wakes to ONE current
command, and a stop can structurally never be the update an overflowing queue drops.

New API/ABI: NativeClient::{next_rumble_command,set_rumble_quirks} +
punktfunk_connection_next_rumble_cmd/_set_rumble_quirks (next_rumble/next_rumble2 stay for
un-migrated embedders; both consumers are fed). Migrations DELETE the platform forks:
pf-client-core loses RumbleState + the Deck keepalive loop + LEGACY_RUMBLE_CEILING_MS and
physically silences a slot at close; Android loses the 60 s legacy one-shot (backstop
repack, cancel-on-zero); Apple loses envelopeDeadline + sessionStaleSeconds + both tick
watchdogs (CoreHaptics realization untouched; mac xcframework rebuilt locally).

design/rumble-root-fix.md par. D. Engine 10/10 unit tests; core tests 176 Linux / 175
Windows + clippy -D warnings; swift build + RumbleTuningTests; Kotlin + android-native
compile green.

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

clients/apple/Sources/PunktfunkKit/Connection/PunktfunkConnection.swift

@@ -777,6 +777,34 @@ public final class PunktfunkConnection {
         }
     }
 
+    /// Pull the next EFFECTIVE rumble command from the core's shared rumble policy engine — the
+    /// uniform replacement for per-platform rumble policy. The engine owns every decision
+    /// (v2 lease expiry, legacy-host staleness at a uniform 1 s, connection-close drain zeros),
+    /// so apply commands verbatim: `(0, 0)` = stop now, non-zero = run at this level.
+    /// `backstopMs` is a safety-net duration for duration-parameterized platform APIs — the
+    /// CoreHaptics renderer ignores it (its finite segment ceiling is the equivalent net).
+    /// Drain from the (single) feedback thread, alongside `nextHidOutput`.
+    public func nextRumbleCommand(timeoutMs: UInt32 = 0) throws
+        -> (pad: UInt16, low: UInt16, high: UInt16, backstopMs: UInt32)?
+    {
+        feedbackLock.lock()
+        defer { feedbackLock.unlock() }
+        guard let h = liveHandle() else { throw PunktfunkClientError.closed }
+
+        var pad: UInt16 = 0, low: UInt16 = 0, high: UInt16 = 0, backstop: UInt32 = 0
+        let rc = punktfunk_connection_next_rumble_cmd(h, &pad, &low, &high, &backstop, timeoutMs)
+        switch rc {
+        case statusOK:
+            return (pad, low, high, backstop)
+        case statusNoFrame:
+            return nil
+        case statusClosed:
+            throw PunktfunkClientError.closed
+        default:
+            throw PunktfunkClientError.status(rc)
+        }
+    }
+
     /// One DualSense feedback event a game wrote to the host's virtual pad — replay it on
     /// the real controller (GCDeviceLight, GCControllerPlayerIndex,
     /// GCDualSenseAdaptiveTrigger). Only a `.dualSense` session emits these.

clients/apple/Sources/PunktfunkKit/Gamepad/GamepadFeedback.swift

@@ -155,21 +155,18 @@ public final class GamepadFeedback {
                     // meta, was unaffected). Pacing with a short sleep OUTSIDE the lock (below) keeps
                     // rumble/HID latency low while leaving the lock free between polls.
                     //
-                    // Rumble is idempotent state, so drain the plane DRY and apply only the newest
-                    // level PER PAD. The old one-datagram-per-cycle shape let a burst outpace the
-                    // ~125 Hz drain: levels rendered up to ~130 ms late through the core's 16-deep
-                    // queue, and its drop-newest overflow could shed a stop while stale nonzero
-                    // states queued ahead of it — buzzing until the host's next 500 ms refresh.
-                    var newestByPad: [UInt8: (low: UInt16, high: UInt16, ttl: UInt32)] = [:]
+                    // Rumble arrives as EFFECTIVE commands from the core's shared policy engine
+                    // (design/rumble-root-fix.md §D): the engine owns leases, legacy staleness,
+                    // and close-drain zeros, and its per-pad mailbox already coalesces — a
+                    // stalled drain wakes to ONE current-level command per pad, and a stop can
+                    // never be shed by a queue. Apply verbatim, in order.
                     var rumbleBurst = 0
                     while rumbleBurst < 64, !flag.isStopped,
-                          let r = try connection.nextRumble2(timeoutMs: 0) {
-                        newestByPad[UInt8(truncatingIfNeeded: r.pad)] = (r.low, r.high, r.ttlMs)
+                          let c = try connection.nextRumbleCommand(timeoutMs: 0) {
+                        self?.routeRumble(
+                            pad: UInt8(truncatingIfNeeded: c.pad), low: c.low, high: c.high)
                         rumbleBurst += 1
                     }
-                    for (pad, n) in newestByPad {
-                        self?.routeRumble(pad: pad, low: n.low, high: n.high, ttlMs: n.ttl)
-                    }
                     // Drain a BOUNDED burst of hidout events so sustained 0xCD traffic (a game writing
                     // per-frame LED/trigger reports) can't spin here or block stop() past one cycle.
                     var burst = 0
@@ -218,15 +215,15 @@ public final class GamepadFeedback {
         }
     }
 
-    /// Route one rumble envelope to its pad's renderer (drain thread). An update for a pad with no
+    /// Route one engine command to its pad's renderer (drain thread). A command for a pad with no
     /// live renderer — one that just left the forwarded set — is dropped.
-    private func routeRumble(pad: UInt8, low: UInt16, high: UInt16, ttlMs: UInt32) {
+    private func routeRumble(pad: UInt8, low: UInt16, high: UInt16) {
         let renderer = withRouting { rumbleByPad[pad] }
-        renderer?.apply(low: low, high: high, ttlMs: ttlMs)
+        renderer?.apply(low: low, high: high)
         // The opt-in device mirror follows controller 1 unconditionally — the pads it exists for
         // have no motors (their renderer above no-ops), and mirroring deliberately isn't gated on
         // that: capability probing can't see a motor-less MFi pad, and the user opted in.
-        if pad == 0 { deviceRumble?.apply(low: low, high: high, ttlMs: ttlMs) }
+        if pad == 0 { deviceRumble?.apply(low: low, high: high) }
     }
 
     private func withRouting<R>(_ body: () -> R) -> R {

clients/apple/Sources/PunktfunkKit/Gamepad/RumbleRenderer.swift

@@ -23,23 +23,6 @@ enum RumbleTuning {
     /// the churn that lost stops inside CoreHaptics. Newest level wins when the window opens;
     /// zero is never throttled.
     static let minRebakeSeconds: TimeInterval = 0.025
-    /// Session watchdog: silence the motors when no wire command arrived for this long. This is
-    /// the **legacy-host fallback only** — an old host sends no self-termination lease, so its
-    /// periodic re-send (every 500 ms) is the sole liveness signal and 3 vanished refreshes means
-    /// the channel or host died while audible. A v2 host instead supplies a per-command TTL (see
-    /// [`leaseSeconds`]); that deadline supersedes this watchdog.
-    static let sessionStaleSeconds: TimeInterval = 1.6
-
-    /// The legacy no-lease sentinel a v2 `ttl_ms` carries for an old host (mirrors the C ABI's
-    /// `PUNKTFUNK_RUMBLE_NO_TTL`). `UInt32.max` by construction.
-    static let noTTL: UInt32 = .max
-
-    /// Interpret a wire TTL (ms) from a rumble update: `nil` for the legacy no-lease sentinel
-    /// ([`noTTL`]) — the renderer falls back to [`sessionStaleSeconds`] — else the self-termination
-    /// lease in seconds (render the level for at most this long unless the host renews it).
-    static func leaseSeconds(ttlMs: UInt32) -> TimeInterval? {
-        ttlMs == noTTL ? nil : TimeInterval(ttlMs) / 1000
-    }
     /// Levels closer than this (≈0.4 % of full scale) are the same level — an identical host
     /// refresh must never rebuild a player.
     static let levelEpsilon: Float = 1.0 / 256.0
@@ -110,13 +93,15 @@ enum RumbleTuning {
 /// `@unchecked Sendable` is sound because every property is read and written only inside
 /// `queue` closures — the serial queue is the synchronization.
 final class RumbleRenderer: @unchecked Sendable {
-    /// What an un-refreshed nonzero target means. A live session ties motor life to wire
-    /// liveness (the host refreshes state every 500 ms); the controller test panel holds a
-    /// slider level indefinitely.
+    /// Who ends an un-refreshed nonzero target. Session mode applies the core policy engine's
+    /// commands verbatim — the engine (punktfunk-core `client/rumble.rs`) owns every lease,
+    /// staleness, and close decision and emits explicit zeros, so the renderer keeps NO
+    /// staleness policy of its own anymore. The controller test panel (`manual`) holds a slider
+    /// level indefinitely; both are identical renderer-side today, the distinction is kept for
+    /// the call sites' intent.
     struct Policy {
-        let staleAfter: TimeInterval?
-        static let session = Policy(staleAfter: RumbleTuning.sessionStaleSeconds)
-        static let manual = Policy(staleAfter: nil)
+        static let session = Policy()
+        static let manual = Policy()
     }
 
     /// Which physical actuator this renderer drives: the forwarded controller's haptics engine
@@ -160,13 +145,9 @@ final class RumbleRenderer: @unchecked Sendable {
     private var controller: GCController?
     private var low: Motor?
     private var high: Motor?
-    /// Wire-truth target (raw wire units) and when it was last confirmed by any command.
+    /// Wire-truth target (raw wire units) — the engine command's level, applied verbatim; the
+    /// core policy engine owns when it ends (explicit zero commands), so no deadline lives here.
     private var target: (low: UInt16, high: UInt16) = (0, 0)
-    private var lastCommand = DispatchTime(uptimeNanoseconds: 0)
-    /// The v2 envelope lease: the active level is authorized until here unless the host renews it
-    /// (`tick` silences at the deadline). `nil` against a legacy host (no lease — the
-    /// `sessionStaleSeconds` watchdog is the backstop) and while silent.
-    private var envelopeDeadline: DispatchTime?
     /// Runs while anything is (or should be) audible: staleness watchdog, segment re-arm,
     /// throttled-level catch-up, engine rebuild after a reset, HID keepalive. Nil while silent,
     /// so an idle controller costs no timer wakeups and no radio traffic.
@@ -247,17 +228,9 @@ final class RumbleRenderer: @unchecked Sendable {
     /// against a legacy host (no lease → the staleness watchdog is the backstop). Renewals at an
     /// unchanged level extend the deadline before the idempotence guard, so a held rumble never
     /// lapses mid-effect.
-    func apply(low lowAmp: UInt16, high highAmp: UInt16, ttlMs: UInt32 = RumbleTuning.noTTL) {
+    func apply(low lowAmp: UInt16, high highAmp: UInt16) {
         queue.async {
-            self.lastCommand = .now()
             let active = lowAmp != 0 || highAmp != 0
-            // v2 lease: a nonzero level gets an explicit deadline; a stop or a legacy update clears
-            // it. Set BEFORE the idempotence guard so an identical renewal still extends the lease.
-            if let lease = RumbleTuning.leaseSeconds(ttlMs: ttlMs), active {
-                self.envelopeDeadline = .now() + lease
-            } else {
-                self.envelopeDeadline = nil
-            }
             if active != self.wasActive {
                 self.wasActive = active
                 log.debug(
@@ -275,7 +248,6 @@ final class RumbleRenderer: @unchecked Sendable {
             self.ticker?.cancel()
             self.ticker = nil
             self.target = (0, 0)
-            self.envelopeDeadline = nil
             self.wasActive = false
             self.teardown()
             self.closeHID()
@@ -331,25 +303,11 @@ final class RumbleRenderer: @unchecked Sendable {
         healthSink?(problem)
     }
 
-    /// Watchdog + housekeeping heartbeat while audible.
+    /// Housekeeping heartbeat while audible: segment re-arm, HID keepalive, backoff retries.
+    /// Every liveness decision (lease expiry, legacy-host staleness, session close) lives in the
+    /// core policy engine now — it emits explicit zero commands, so the renderer never guesses
+    /// when a level should end.
     private func tick() {
-        if let deadline = envelopeDeadline {
-            // v2 host lease: silence the moment it lapses unrenewed. This firing in the wild is the
-            // observable signature of a host that stopped renewing (a dropped stop, or a dead host)
-            // — the whole point of the envelope model: the motor can't outlive the host's intent.
-            if target != (0, 0), DispatchTime.now() >= deadline {
-                log.warning("rumble: envelope expired unrenewed — silencing")
-                target = (0, 0)
-                envelopeDeadline = nil
-            }
-        } else if let after = policy.staleAfter, target != (0, 0), seconds(since: lastCommand) > after {
-            // Legacy host (no lease): it re-sends state every 500 ms, so this much silence means the
-            // channel (or host) died while a motor was on. A direct-connected pad would have been
-            // stopped by its game long ago — force the same outcome.
-            log.warning(
-                "rumble: no wire refresh for \(after, format: .fixed(precision: 1), privacy: .public)s — auto-silencing")
-            target = (0, 0)
-        }
         render()
     }