Reconnect to remembered hardware instead of pairing every launch

`remembered` was a HashSet inside DeviceRegistry, so it lasted exactly as
long as the process. Every launch started from nothing: find the trainer,
press Connect, find the strap, press Connect, and only then ride. FR-1.5
has been a Should since the beginning and was never actually true.

It is a file now — devices.json in the app data directory, written when a
link actually comes up rather than when Connect is pressed. A Connect the
hardware then refuses is not a pairing, and writing one down would mean a
trainer the rider gave up on getting chased on every launch afterwards.
Forgetting is recorded too, in its own list: absent means never seen,
forgotten means the rider looked at this device and said no, and
auto-connect has to keep honouring that on the next launch as well. The
file is advisory — a corrupt one costs auto-connect, never a ride.

Auto-connect is driven by the scan rather than fired once at startup. The
hardware is asleep at startup — a trainer wakes when the cranks turn, a
strap when it is put on (A-4) — so a remembered device is reconnected the
moment it advertises, through the same path the rider's own click takes,
scan suspension included. Bounded by AUTO_ATTEMPTS on an AUTO_RETRY
cooldown and cleared when the link comes up or the rider connects by
hand: an app that never stops trying can never honestly say it has
stopped (FR-1.11). A device disconnected by hand is left alone for the
rest of the session, since a disconnect that undoes itself two ticks
later is not a disconnect.

Pods now prefer the pod we know. Every Click advertises the same name and
the same type byte, so before this a rider whose partner was warming up
in the next room got whichever pod woke first. With nothing of that kind
remembered anything still goes, or there could never be a first pairing.

And the pair is one pod, not two. Confirmed on this hardware 2026-08-21:
pairing the − pod alone delivers all ten buttons, its twin's included —
which §2.3.1 had established for the frames but not for the pairing. So
take_plus_pod holds the + pod back while a known − pod may merely be
asleep, and connect_controller with no pod named means the − pod rather
than both. The wait is bounded by PLUS_GRACE, because a flat − pod should
cost the rider a D-pad and not a controller, and Buttons is untouched: it
is what makes the handover between the two configurations invisible.

Not yet tested against real hardware — nothing was advertising here. The
store, the retry budget and the pod-preference rules have unit tests, and
a seeded devices.json was confirmed to load and seed the − pod at launch,
but the connect path itself waits for a ride.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

ui/src/components/ClickPanel.svelte

@@ -1,24 +1,31 @@
 <script lang="ts">
   /**
-   * The Zwift Click, as two pods (FR-1.4, FR-9.1–9.2).
+   * The Zwift Click (FR-1.4, FR-9.1–9.2).
    *
-   * A Click v2 is **two peripherals**, and until now the app showed one line
-   * for both: connect, and you got whichever pod answered first, with no way to
-   * tell which one that was or that the other was missing entirely. Each pod
-   * now has a card of its own — its own state, battery, address and proof that
-   * its buttons arrive.
+   * A Click v2 is two peripherals, but it is **one controller**: connected on
+   * its own, the `−` pod delivers all ten buttons — its own paddle and D-pad,
+   * *and* the `+` paddle and face buttons relayed from its twin (§2.3.1,
+   * confirmed on this hardware 2026-08-21). So one link is the whole thing, and
+   * this panel says so rather than presenting two halves that both look
+   * required. Pairing both is not merely redundant: it is the configuration in
+   * which the `−` pod stops reporting its own paddle.
+   *
+   * The `+` pod keeps a card, because it is the fallback that matters when the
+   * `−` pod is flat or left in the garage — a rider with one working pod should
+   * still get a working controller.
    *
    * They are named for the shift paddle each carries, not for the side of the
    * bar. Nothing a pod advertises says which end of the handlebar it is
    * clamped to, so left and right would be a guess; the paddle is printed on
    * the pod, and pressing it settles the question on screen (`confirmed`).
    *
-   * The second job of this panel is to say what to *do* when a pod is missing.
-   * A Click sleeps within seconds and only advertises while awake (A-4), which
-   * no rider can guess from the words "not connected" — and which is also why
-   * connecting is not a button they have to win a race with: the running scan
-   * picks a pod up the moment it wakes and connects it (FR-1.5). The buttons
-   * here are for overriding that, not for driving it.
+   * The second job of this panel is to say what to *do* when nothing is
+   * connected. A Click sleeps within seconds and only advertises while awake
+   * (A-4), which no rider can guess from the words "not connected" — and which
+   * is also why connecting is not a button they have to win a race with: the
+   * running scan picks a pod up the moment it wakes and connects it (FR-1.5),
+   * and once paired it goes back to the pod it knows. The buttons here are for
+   * overriding that, not for driving it.
    */
   import { app } from '../lib/app.svelte';
   import { api, type Pod, type PodState, type PodStatus } from '../lib/bridge';
@@ -29,7 +36,11 @@
    *  pod stays missing — and the fix belongs next to the symptom. */
   const scanning = $derived(app.devices.scanning);
   const anyConnected = $derived(pods.some((p) => p.state === 'connected'));
-  const bothConnected = $derived(pods.length === 2 && pods.every((p) => p.state === 'connected'));
+  /** The pod that speaks for the pair. Connected, this is the whole controller. */
+  const minusLive = $derived(controller?.minus.state === 'connected');
+  /** Running on the fallback: the `+` pod alone, with no `−` paddle to shift
+   *  down with beyond its `Y` button. Worth saying out loud. */
+  const plusOnly = $derived(!minusLive && controller?.plus.state === 'connected');
   const busy = $derived(pods.some((p) => p.state === 'searching'));
   /** A pod reporting the other's paddle: the pair may be filed the wrong way
    *  round, and the rider is the only one who can say. */
@@ -53,8 +64,8 @@
 
   /** What each pod is for, so a rider who has lost one knows what they lost. */
   const PURPOSE: Record<Pod, string> = {
-    minus: 'Shift down · D-pad',
-    plus: 'Shift up · A B Y Z',
+    minus: 'All ten buttons · relays the + pod',
+    plus: 'Fallback · shift up, A B Y Z',
   };
 
   function connect(pod: Pod) {
@@ -69,13 +80,13 @@
 <section class="click">
   <header>
     <h2>Zwift Click</h2>
-    <span class="summary" class:tone-ok={bothConnected} class:tone-warn={!bothConnected}>
-      {#if bothConnected}
-        Both pods connected
-      {:else if anyConnected}
-        One pod of two
+    <span class="summary" class:tone-ok={anyConnected} class:tone-warn={!anyConnected}>
+      {#if minusLive}
+        Connected · all ten buttons
+      {:else if plusOnly}
+        + pod only
       {:else}
-        No pods connected
+        Not connected
       {/if}
     </span>
     <div class="actions">
@@ -83,14 +94,16 @@
         <!-- Nothing can be picked up automatically while the scan is off, so
              the way to fix that sits here rather than only in the header. -->
         <button class="btn" onclick={() => app.run(() => api.startScan())}>Start scan</button>
-      {:else if !bothConnected}
+      {:else if !minusLive}
+        <!-- The − pod, not both: it is the one that carries the whole
+             controller. The + pod has its own button on its own card. -->
         <button class="btn" disabled={busy} onclick={() => app.run(() => api.connectController())}>
-          {busy ? 'Searching…' : 'Connect now'}
+          {busy ? 'Searching…' : 'Look for the − pod'}
         </button>
       {/if}
       {#if anyConnected}
         <button class="btn ghost" onclick={() => app.run(() => api.disconnectController())}>
-          Disconnect both
+          Disconnect
         </button>
       {/if}
     </div>
@@ -99,11 +112,16 @@
   <p class="lede">
     {#if !scanning}
       <strong>The scan is off</strong>, so pods will not be picked up. Start it and press a button
-      on each pod.
-    {:else if bothConnected}
-      Both pods are connected and will reconnect on their own if one drops.
+      on a pod.
+    {:else if minusLive}
+      The <strong>− pod is connected</strong>, and it relays its twin: all ten buttons arrive over
+      this one link. There is nothing to pair the + pod for. It reconnects on its own if it drops,
+      and on the next launch.
+    {:else if plusOnly}
+      Running on the <strong>+ pod alone</strong> — its paddle, face buttons and shift-down on
+      <span class="kbd">Y</span>. Press a button on the − pod to get the D-pad back.
     {:else}
-      <strong>Press any button on a missing pod.</strong> It only advertises while awake, and the
+      <strong>Press any button on the − pod.</strong> It only advertises while awake, and the
       running scan connects it as soon as it does — no need to press anything here.
     {/if}
   </p>
@@ -142,7 +160,13 @@
           </div>
         </dl>
 
-        {#if pod.confirmed}
+        {#if pod.pod === 'plus' && minusLive && pod.state !== 'connected'}
+          <!-- Not a fault, and the panel must not let it read as one: this pod
+               is idle because the − pod is already sending its buttons. -->
+          <p class="note tone-ok">
+            Not needed — the − pod is relaying this pod's paddle and face buttons.
+          </p>
+        {:else if pod.confirmed}
           <p class="note tone-ok">Confirmed — this pod sent its own {pod.symbol} paddle.</p>
         {:else if pod.state === 'connected'}
           <p class="note">
@@ -168,7 +192,7 @@
             <button class="btn ghost" onclick={() => disconnect(pod.pod)}>Stop searching</button>
           {:else}
             <button class="btn ghost" onclick={() => connect(pod.pod)}>
-              Look for it now
+              {pod.pod === 'plus' && minusLive ? 'Connect anyway' : 'Look for it now'}
             </button>
           {/if}
         </div>
@@ -195,15 +219,14 @@
     </div>
   {/if}
 
-  {#if !bothConnected}
+  {#if !minusLive}
     <!--
-      FR-1.8 / FR-3.10. "Not connected" on its own reads as a broken app. Both
-      real causes — a sleeping pod and a lapsed unlock — are things only the
-      rider can fix, so they are spelled out here rather than left to be
-      guessed at.
+      FR-1.8. "Not connected" on its own reads as a broken app, and the real
+      cause — a pod that is simply asleep — is something only the rider can fix,
+      so it is spelled out here rather than left to be guessed at.
     -->
     <details class="help" open={!anyConnected}>
-      <summary>A pod will not connect — what to try</summary>
+      <summary>The − pod will not connect — what to try</summary>
       <ol>
         <li>
           <strong>Press any button on the pod.</strong> This is almost always the whole answer.
@@ -224,6 +247,12 @@
           altogether, and after about thirty failed attempts the app stops chasing it and says
           so on the card.
         </li>
+        <li>
+          <strong>Use the + pod instead.</strong> If the − pod is flat or not with you, the app
+          falls back to the + pod on its own after about a minute — or press
+          <em>Look for it now</em> on its card. You lose the D-pad; <span class="kbd">Y</span>
+          still shifts down.
+        </li>
       </ol>
       <p class="fallback">
         Meanwhile the keyboard mirrors every Click action — <span class="kbd">+</span>

ui/src/components/ConnectionScreen.svelte

@@ -92,7 +92,17 @@
       {@const bars = rssiBars(device.rssi)}
       <article class="row" class:live={isConnected(device)}>
         <div class="identity">
-          <span class="name">{device.name}</span>
+          <span class="name">
+            {device.name}
+            <!-- FR-1.5. Paired before, so it comes back on its own the next
+                 time it advertises — this launch or any other. Worth a badge:
+                 it is the difference between a device the rider has to fetch
+                 and one that simply turns up, and Forget below is how they
+                 take it back. -->
+            {#if device.remembered}
+              <span class="badge" title="Paired before — reconnects on its own">Remembered</span>
+            {/if}
+          </span>
           <span class="meta">{KIND_LABEL[device.kind]} · {device.address}</span>
           {#if device.error}
             <span class="error">{device.error}</span>
@@ -324,6 +334,10 @@
   }
 
   .name {
+    display: flex;
+    align-items: baseline;
+    gap: 0.45rem;
+    min-width: 0;
     font-size: 1.12rem;
     font-weight: 600;
     letter-spacing: -0.01em;
@@ -332,6 +346,18 @@
     text-overflow: ellipsis;
   }
 
+  .badge {
+    flex: none;
+    padding: 0.1rem 0.4rem;
+    border: 1px solid var(--hairline);
+    border-radius: 0.3rem;
+    color: var(--ink-dim);
+    font-size: 0.68rem;
+    font-weight: 600;
+    letter-spacing: 0.04em;
+    text-transform: uppercase;
+  }
+
   .meta {
     font-size: 0.8rem;
     color: var(--ink-dim);