feat: smarter rotator polling - interleaved timer, adaptive rate, tolerance

- Replace dual setInterval with single setTimeout chain alternating
  poll → track phases, avoiding back-to-back commands on serial links
- Adaptive poll rate derived from rotator velocity (250ms at full slew,
  3s when idle), no extra config needed
- Skip redundant track commands when target hasn't moved >0.05°
- Add configurable tolerance (GPredict-style): suppress position commands
  when rotator is already within threshold of target, reducing gear wear
- Fix azimuth wraparound in velocity, slew detection, and skip checks
- Map Hamlib RPRT error codes to human-readable messages
- Default WebSocket URL to ws://localhost:4534 to match docs
- Update network guide with clearer install/run steps for bridges

Author: sandrwich

src/rotator/rotctld.ts

@@ -27,7 +27,7 @@ export class RotctldDriver implements RotatorDriver {
   }
 
   async connect(options: RotatorConnectOptions): Promise<void> {
-    const url = options.wsUrl ?? 'ws://localhost:4533';
+    const url = options.wsUrl ?? 'ws://localhost:4534';
     return new Promise<void>((resolve, reject) => {
       const ws = new WebSocket(url, ['binary']);
       ws.binaryType = 'arraybuffer';
@@ -169,10 +169,33 @@ export class RotctldDriver implements RotatorDriver {
   }
 }
 
+/**
+ * Hamlib error codes → human-readable descriptions.
+ * @see https://github.com/Hamlib/Hamlib/blob/master/include/hamlib/rig.h — rig_errcode_e
+ */
+const RPRT_ERRORS: Record<string, string> = {
+  '-1': 'Invalid parameter (check az/el limits)',
+  '-2': 'Invalid configuration',
+  '-3': 'Out of memory',
+  '-4': 'Not implemented',
+  '-5': 'Communication timed out',
+  '-6': 'I/O error',
+  '-7': 'Internal error',
+  '-8': 'Protocol error',
+  '-9': 'Command rejected',
+  '-10': 'Argument truncated',
+  '-11': 'Not available',
+  '-12': 'Target not available',
+  '-13': 'Bus error',
+  '-14': 'Bus busy / collision',
+  '-17': 'Argument out of range',
+};
+
 /** Throw if rotctld returned an error code (RPRT -N). */
 function checkRprt(response: string): void {
   const match = response.match(/RPRT\s+(-\d+)/);
   if (match) {
-    throw new Error(`rotctld error: RPRT ${match[1]}`);
+    const desc = RPRT_ERRORS[match[1]] ?? `unknown error ${match[1]}`;
+    throw new Error(desc);
   }
 }