feat: add remote device management and pairing functionality

- Implemented device pairing with a four-digit code and TTL for remote settings.
- Introduced automatic checks for device status and configuration validation.
- Developed UI components for device setup and management, including error handling and retry options.
- Created a device bridge for secure communication between the device and the server.
- Added tests for managed state validation and device pairing logic.
- Established a local end-to-end fixture for testing device service and API interactions.

src/styles.css

@@ -515,3 +515,6 @@ h1 { font-size: clamp(30px, 3.8vw, 76px); letter-spacing: -.05em; line-height: 1
   .destination-old { visibility: hidden; }
   .destination-current { transform: none !important; }
 }
+
+/* Device onboarding keeps the same black/lime typography as the board. */
+.device-setup{min-height:100dvh;background:#000;color:#fff;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:clamp(24px,4vw,64px);text-align:center;gap:clamp(22px,4vh,48px);--accent:#d5ff70}.device-setup-brand{display:flex;align-items:center;gap:12px;font-size:32px;font-weight:800;letter-spacing:-.07em}.device-setup-brand>span{display:block;width:48px;color:var(--accent)}.device-setup-brand svg{width:100%;height:auto}.device-setup-card{width:min(850px,100%);border:1px solid #38402a;border-radius:32px;padding:clamp(22px,4vw,52px);background:radial-gradient(ellipse at top,#d5ff7011,transparent 65%)}.device-setup-card h1{font-size:clamp(30px,4.4vw,62px);margin:12px 0 18px;letter-spacing:-.055em}.device-setup-card p{font-size:clamp(18px,2vw,26px);color:#b3b9aa;max-width:640px;margin:0 auto;line-height:1.4}.device-pair-code{display:flex;justify-content:center;font-weight:750;font-size:clamp(64px,min(14vw,18vh),150px);letter-spacing:.08em;margin:22px 0;color:var(--accent)}.device-pair-expiry{display:flex;justify-content:center;align-items:center;gap:10px;font-size:clamp(18px,2vw,24px);color:#b3b9aa}.device-pair-expiry .numeric-text{color:var(--accent)}.device-setup button,.managed-panel button{display:inline-flex;align-items:center;justify-content:center;gap:10px;padding:14px 20px;font-size:18px;border:1px solid #555;border-radius:14px;color:#fff;background:#161616;min-height:50px}.device-setup-card button{margin-top:24px}.device-setup-card a{display:block;margin-top:20px;color:var(--accent);font-size:20px}.device-setup-status{color:#ffd479;margin-top:20px;font-size:18px}.managed-panel{color:var(--text);background:var(--background,#000);border:1px solid var(--border,#555);border-radius:26px;padding:32px;width:min(600px,calc(100% - 32px));max-height:calc(100dvh - 32px);overflow:auto}.managed-panel::backdrop{background:#000a;backdrop-filter:blur(8px)}.managed-panel>svg{color:var(--accent)}.managed-panel h2{font-size:28px;margin:16px 0}.managed-panel strong{font-size:22px;color:var(--accent)}.managed-panel p{font-size:18px;line-height:1.5;margin:16px 0;color:var(--muted,#aaa)}.managed-panel dl{display:grid;grid-template-columns:1fr 1fr;gap:12px;font-size:16px;margin:20px 0}.managed-panel>div{display:flex;gap:12px;flex-wrap:wrap}.managed-offline{color:var(--warning);font-size:14px;position:fixed;top:8px;left:50%;transform:translateX(-50%);background:var(--background,#000);padding:6px 12px;border-radius:10px;z-index:3;max-width:90vw;text-align:center}@media(max-height:650px){.device-setup{gap:16px;padding:20px}.device-setup-card{padding:24px}.device-pair-code{margin:14px 0}.device-setup-brand{font-size:26px}.device-setup-brand>span{width:36px}}