op25: pin gr310 to 5b58335; analog defaults to OP25 noise squelch (node-26#46, node-26#29)

- op25-container/Dockerfile: clone gr310 then check out 5b58335 (OP25_COMMIT
  build arg). That is the gr310 merge tk_drb_conv was verified against for
  #29 and the first carrying PR #296's NBFM noise/voice squelch. Changing
  the RUN line also busts CI's cached unpinned clone.
- Keys verified from op25_nbfm.py at that commit: nbfm_squelch_mode
  (power|noise|voice), nbfm_noise_squelch_db, nbfm_squelch_threshold, read
  from the channel dict.
- op25-container: ConfigGenerator.nbfm_squelch_mode (enum, default noise) and
  nbfm_noise_squelch_db, written onto the analog channel.
- edge-node: system config squelch_mode / squelch_db / squelch_threshold ->
  generate payload (validated, noise when absent); /api/listen and the
  dashboard's analog pane expose mode and level.

#29's CI test of tk_drb_conv against the real tk_p25.py is not done here.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-edge-node/app/routers/api.py

@@ -208,6 +208,12 @@ class ListenBody(BaseModel):
     frequencies: List[float] = []
     talkgroups: List[Talkgroup] = []       # p25 only; empty = every talkgroup
     nac: Optional[str] = None              # p25conv only, hex; empty = any NAC
+    # analog only (node-26#46): OP25 squelch. noise (default) needs no
+    # calibration; squelch_db = dB of quieting to open (OP25 default 8);
+    # squelch_threshold = absolute dB for power mode (OP25 default -60).
+    squelch_mode: Optional[Literal["noise", "voice", "power"]] = None
+    squelch_db: Optional[float] = None
+    squelch_threshold: Optional[float] = None
 
 
 # RTL-SDR (R820T/R828D) tuning range.
@@ -242,14 +248,21 @@ async def listen(body: ListenBody):
         else:
             is_p25 = body.mode == "p25"
             label = (body.name or "").strip() or (f"P25 {first} MHz" if is_p25 else f"Analog {first} MHz")
+            sys_config = {
+                "control_channels": freqs,
+                "talkgroups": [tg.model_dump() for tg in body.talkgroups] if is_p25 else [],
+            }
+            if not is_p25:
+                sys_config["squelch_mode"] = body.squelch_mode or "noise"
+                if body.squelch_db is not None:
+                    sys_config["squelch_db"] = body.squelch_db
+                if body.squelch_threshold is not None:
+                    sys_config["squelch_threshold"] = body.squelch_threshold
             config = SystemConfig(
                 system_id=f"local-{body.mode}",
                 name=label,
                 type="P25" if is_p25 else "NBFM",
-                config={
-                    "control_channels": freqs,
-                    "talkgroups": [tg.model_dump() for tg in body.talkgroups] if is_p25 else [],
-                },
+                config=sys_config,
             )
     await _apply_override(config)
     return {"ok": True, "name": config.name}