istrain-public: from-scratch build of a passive RF train detector

Public community release. The complete working system — DSP + decoders (scripts/),
web dashboard + API (dashboard/), container stack (docker/), config templates (config/) —
plus APOCALYPSE-EDITION.md, the full build guide for a human or a coding agent. GPLv3
(PyEOT dependency). Scrubbed of all secrets, internal IPs, hostnames, and location detail.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/trim-captures.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+# trim-captures — prune old VOICE capture audio from /tmp/airband, keeping the durable detection log.
+# Safe by design: heard.jsonl (the detections Activity reads — channel + time) is SEPARATE and never
+# touched; this only deletes bulky .mp3 audio AFTER it's logged. It forces an ingest first (GET /api/heard,
+# which appends any new clip to heard.jsonl) and ABORTS if the dashboard is unreachable — so a not-yet-logged
+# clip can never be deleted. --dry-run to preview.
+import os, glob, time, sys, urllib.request
+
+CAP = os.environ.get("AIRBAND_DIR", "/tmp/airband")
+KEEP_HOURS = float(os.environ.get("CAP_KEEP_HOURS", "24"))
+DASH = os.environ.get("DASH_URL", "http://127.0.0.1:8157")
+DRY = "--dry-run" in sys.argv
+
+def main():
+    try:                                            # log every current clip to heard.jsonl first
+        urllib.request.urlopen(DASH + "/api/heard", timeout=10).read()
+    except Exception as e:
+        print(f"[trim] dashboard unreachable ({e}) — NOT trimming (clips may be unlogged)"); return
+    cutoff = time.time() - KEEP_HOURS * 3600
+    mp3s = glob.glob(os.path.join(CAP, "*.mp3"))
+    old = [m for m in mp3s if os.path.getmtime(m) < cutoff]
+    freed = 0
+    for m in old:
+        freed += os.path.getsize(m)
+        if not DRY:
+            try: os.remove(m)
+            except OSError: pass
+            # whisper sidecar (2026-07-10) rides with its clip — no orphan .txt buildup
+            try: os.remove(m[:-4] + ".txt")
+            except OSError: pass
+    print(f"[trim{' DRY' if DRY else ''}] {len(mp3s)} clips on disk, deleted {len(old)} older than "
+          f"{KEEP_HOURS:.0f}h, freed {freed//1024} KB; heard.jsonl untouched")
+
+if __name__ == "__main__":
+    main()