fix(client/android): stop reporting every disconnect as a lost connection

The stream watchdog polled a bare "has the session ended" boolean, so it
had exactly one thing it could say and said it every time: "Connection
lost — the host may be asleep. Wake it to reconnect." That ran when the
player quit their game, when an operator ended the session from the
console, and when they pressed Back themselves — telling them to go wake
a host that was never asleep.

It now reads the end reason. Only a connection that actually died gets
that line, a host-side failure gets its own, and the three deliberate
endings say nothing at all: leaving the stream is already the feedback,
and a toast on top of it is just noise.

A game launched from a library also returns to that library instead of
host selection, which needs the intent hoisted out of the console shell:
the stream replaces that shell in the composition, discarding the
`remember`s holding its screen and host, so by the time the session ends
there is nothing left to navigate back with. The parent holds it across
the gap and the shell consumes it on the way in. The touch UI has no
library — only the console shell does — so there it is the toast fix
alone.

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/NativeBridge.kt

@@ -87,6 +87,18 @@ object NativeBridge {
      */
     external fun nativeSessionEnded(handle: Long): Boolean
 
+    /**
+     * WHY the session ended, as a [SessionEndReason] ordinal — decode with
+     * [SessionEndReason.fromNative]. `0` (NONE) before it ends, or on a `0` handle.
+     *
+     * The companion to [nativeSessionEnded], which only says THAT it ended. Both are needed: the
+     * flag to leave a dead stream, this to decide what to tell the user. A player quitting their
+     * game and a host falling off the network both end the session, and with no way to separate
+     * them the watchdog said "the host may be asleep" for all of them — wrong for every deliberate
+     * ending. Cheap (one atomic load); UI-safe.
+     */
+    external fun nativeEndReason(handle: Long): Int
+
     /**
      * Run the SPAKE2 PIN ceremony, presenting [certPem]/[keyPem]. Returns the host's verified
      * fingerprint (64-hex) to persist + pin, or `""` on failure (wrong PIN / MITM / unreachable).

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/SessionEndReason.kt

@@ -0,0 +1,56 @@
+package io.unom.punktfunk.kit
+
+/**
+ * Why a stream session ended — the Kotlin mirror of `punktfunk_core::client::PunktfunkEndReason`,
+ * read via [NativeBridge.nativeEndReason].
+ *
+ * The distinction that matters to a UI is **normal vs alarming**, and it is not a spectrum: a
+ * player quitting their game and a host falling off the network both arrive as "the session
+ * ended". With no way to tell them apart this client showed one message for all of them — and it
+ * was the alarming one ("Connection lost — the host may be asleep"), in front of players who had
+ * just quit their own game.
+ *
+ * Ordinals are an ABI contract with the Rust side: append only, never renumber.
+ */
+enum class SessionEndReason {
+    /** Not ended, or ended before a reason could be observed. Also the fallback for an unknown value. */
+    NONE,
+
+    /** This client closed the session — the user pressed back or stop. Nothing to report. */
+    LOCAL,
+
+    /**
+     * The host's launched game exited. A normal finish, and the one reason worth acting on: go back
+     * to the library the title was launched from, so the next one is a tap away.
+     */
+    GAME_EXITED,
+
+    /** The host ended the session deliberately (an operator "End", or it simply finished). Normal. */
+    HOST_ENDED,
+
+    /** The host closed reporting a failure of its own. Worth showing; the host's log has the detail. */
+    HOST_ERROR,
+
+    /**
+     * The connection died rather than being closed: idle timeout, reset, the network going away.
+     * This — and only this — is the "the host may be asleep, wake it" case.
+     */
+    LOST;
+
+    /**
+     * Is this an ordinary outcome rather than something to alarm the user about?
+     *
+     * The question nearly every caller actually asks. [LOCAL], [GAME_EXITED] and [HOST_ENDED] were
+     * all meant to happen. [NONE] counts as normal — no evidence of trouble is not evidence of it.
+     */
+    val isNormal: Boolean
+        get() = this != HOST_ERROR && this != LOST
+
+    companion object {
+        /**
+         * Decode the JNI byte. An unrecognized value becomes [NONE] rather than throwing: this
+         * crosses an ABI where the native side may be newer than this code.
+         */
+        fun fromNative(v: Int): SessionEndReason = entries.getOrNull(v) ?: NONE
+    }
+}