android: the handoff — the pending rounds, the pipeline, and what is unverified

Everything written this session that has not been through the device: rounds 43
to 48 (each patch adversarially verified, 43's transient-notice expectation
fixed), a partial round 49, the pipeline scripts, the Android Auto design and
the icon comparison mock. Also the two harness changes that were never A/B'd —
adaptive waits, which may only shorten a declared wait and never lengthen it,
and a ship that runs the mock walk and the deploy at the same time. The A/B and
its 255-step baseline are in handoff/tools; main stays at what the phone has
actually walked.

handoff/rounds/ins-r46-rust-fields.txt

@@ -0,0 +1,20 @@
+    #[serde(default = "yes")]
+    pub has_prev: bool,
+    /// The queue around what is playing: the current item and up to ten
+    /// either side, rebuilt on every update.
+    ///
+    /// NOTHING READS IT YET, and that is the point — `MediaService` ignores
+    /// both of these fields, so the card is exactly the card it was. media3's
+    /// `SimpleBasePlayer.getState()` wants a playlist and an index into it,
+    /// and when that migration comes the data it needs should have been
+    /// running on the phone for a while rather than have been written the
+    /// same day.
+    ///
+    /// A CAP, not a length: a two-thousand-track queue crosses the bridge as
+    /// twenty-one entries exactly like a twenty-one-track one does.
+    #[serde(default)]
+    pub queue: Vec<QueueItem>,
+    /// Where the current item sits IN `queue` — not in the whole queue.
+    /// `None` when the window is empty.
+    pub queue_index: Option<u32>,
+}