Fix setup.sh hanging on Python 3.14/macOS and add satellite enhancements

- Add --no-cache-dir and --timeout 120 to all pip calls to prevent hanging
  on corrupt/stale pip HTTP cache (cachecontrol .pyc issue)
- Replace silent python -c import verification with pip show to avoid
  import-time side effects hanging the installer
- Switch optional packages to --only-binary :all: to skip source compilation
  on Python versions without pre-built wheels (prevents gevent/numpy hangs)
- Warn early when Python 3.13+ is detected that some packages may be skipped
- Add ground track caching with 30-minute TTL to satellite route
- Add live satellite position tracker background thread via SSE fanout
- Add satellite_predict, satellite_telemetry, and satnogs utilities

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

utils/satnogs.py

@@ -0,0 +1,145 @@
+"""SatNOGS transmitter data.
+
+Fetches downlink/uplink frequency data from the SatNOGS database,
+keyed by NORAD ID. Cached for 24 hours to avoid hammering the API.
+"""
+
+from __future__ import annotations
+
+import json
+import threading
+import time
+import urllib.request
+
+from utils.logging import get_logger
+
+logger = get_logger("intercept.satnogs")
+
+# ---------------------------------------------------------------------------
+# Module-level cache
+# ---------------------------------------------------------------------------
+
+_transmitters: dict[int, list[dict]] = {}
+_fetched_at: float = 0.0
+_CACHE_TTL = 86400  # 24 hours in seconds
+_fetch_lock = threading.Lock()
+
+_SATNOGS_URL = "https://db.satnogs.org/api/transmitters/?format=json"
+_REQUEST_TIMEOUT = 15  # seconds
+
+
+# ---------------------------------------------------------------------------
+# Internal helpers
+# ---------------------------------------------------------------------------
+
+
+def _hz_to_mhz(value: float | int | None) -> float | None:
+    """Convert a frequency in Hz to MHz, returning None if value is None."""
+    if value is None:
+        return None
+    return float(value) / 1_000_000.0
+
+
+def _safe_float(value: object) -> float | None:
+    """Return a float or None, silently swallowing conversion errors."""
+    if value is None:
+        return None
+    try:
+        return float(value)  # type: ignore[arg-type]
+    except (TypeError, ValueError):
+        return None
+
+
+# ---------------------------------------------------------------------------
+# Public API
+# ---------------------------------------------------------------------------
+
+
+def fetch_transmitters() -> dict[int, list[dict]]:
+    """Fetch transmitter records from the SatNOGS database API.
+
+    Makes a single HTTP GET to the SatNOGS transmitters endpoint, groups
+    results by NORAD catalogue ID, and converts all frequency fields from
+    Hz to MHz.
+
+    Returns:
+        A dict mapping NORAD ID (int) to a list of transmitter dicts.
+        Returns an empty dict on any network or parse error.
+    """
+    try:
+        logger.info("Fetching SatNOGS transmitter data from %s", _SATNOGS_URL)
+        with urllib.request.urlopen(_SATNOGS_URL, timeout=_REQUEST_TIMEOUT) as resp:
+            raw = resp.read()
+
+        records: list[dict] = json.loads(raw)
+
+        grouped: dict[int, list[dict]] = {}
+        for item in records:
+            norad_id = item.get("norad_cat_id")
+            if norad_id is None:
+                continue
+
+            norad_id = int(norad_id)
+
+            entry: dict = {
+                "description": str(item.get("description") or ""),
+                "downlink_low": _hz_to_mhz(_safe_float(item.get("downlink_low"))),
+                "downlink_high": _hz_to_mhz(_safe_float(item.get("downlink_high"))),
+                "uplink_low": _hz_to_mhz(_safe_float(item.get("uplink_low"))),
+                "uplink_high": _hz_to_mhz(_safe_float(item.get("uplink_high"))),
+                "mode": str(item.get("mode") or ""),
+                "baud": _safe_float(item.get("baud")),
+                "status": str(item.get("status") or ""),
+                "type": str(item.get("type") or ""),
+                "service": str(item.get("service") or ""),
+            }
+
+            grouped.setdefault(norad_id, []).append(entry)
+
+        logger.info(
+            "SatNOGS fetch complete: %d satellites with transmitter data",
+            len(grouped),
+        )
+        return grouped
+
+    except Exception as exc:  # noqa: BLE001
+        logger.warning("Failed to fetch SatNOGS transmitter data: %s", exc)
+        return {}
+
+
+def get_transmitters(norad_id: int) -> list[dict]:
+    """Return cached transmitter records for a given NORAD catalogue ID.
+
+    Refreshes the in-memory cache from the SatNOGS API when the cache is
+    empty or older than ``_CACHE_TTL`` seconds (24 hours).
+
+    Args:
+        norad_id: The NORAD catalogue ID of the satellite.
+
+    Returns:
+        A (possibly empty) list of transmitter dicts for that satellite.
+    """
+    global _transmitters, _fetched_at  # noqa: PLW0603
+
+    with _fetch_lock:
+        age = time.time() - _fetched_at
+        if not _transmitters or age > _CACHE_TTL:
+            _transmitters = fetch_transmitters()
+            _fetched_at = time.time()
+
+        return _transmitters.get(int(norad_id), [])
+
+
+def refresh_transmitters() -> int:
+    """Force-refresh the transmitter cache regardless of TTL.
+
+    Returns:
+        The number of satellites (unique NORAD IDs) with transmitter data
+        after the refresh.
+    """
+    global _transmitters, _fetched_at  # noqa: PLW0603
+
+    with _fetch_lock:
+        _transmitters = fetch_transmitters()
+        _fetched_at = time.time()
+        return len(_transmitters)