Add P25 Call Alert (TSBK 0x1F) ingest and display

[hoosierscanner]

⚠️ HARD DEPENDENCY — DO NOT MERGE UNTIL BOTH UPSTREAM PRs ARE MERGED ⚠️

This PR will not function without the following two PRs being merged first. There is no trunk-recorder code to emit call_alert MQTT messages until they land:

#	Repo	What it does	Status needed
TrunkRecorder/trunk-recorder#1126	trunk-recorder	Decodes TSBK opcode 0x1F into a CALL_ALERT message type and dispatches it through the plugin API	Must merge first
TrunkRecorder/tr-plugin-mqtt#8	tr-plugin-mqtt	Implements unit_call_alert() in mqtt_status plugin — publishes payload to tr/units/{sys_name}/call_alert	Must merge second

If either is missing, trunk-recorder silently drops all Call Alert TSBK messages and tr-engine receives nothing on this topic.

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What is a P25 Call Alert?

A Call Alert (TSBK opcode 0x1F) is a directed unit-to-unit page — one radio paging another with no voice channel. Common use: CAD dispatcher silently paging an individual officer. No audio. The MQTT message carries source unit and target unit IDs only.

MQTT topic: tr/units/{sys_name}/call_alert

Changes

Ingest (internal/ingest/)

• router.go — routes tr/units/{sys}/call_alert to the unit_event handler as subtype call_alert
• messages.go — adds TargetUnit / TargetUnitAlphaTag fields to UnitEventData
• handler_units.go — upserts source and target units, stores target_unit in metadata_json, publishes SSE as unit_event:call_alert with target_unit and target_unit_alpha_tag
• router_test.go, handler_units_test.go — full test coverage

API (openapi.yaml)

• Adds call_alert to the EventType enum
• Documents target_unit / target_unit_alpha_tag SSE payload fields

Web UI

• events.html (Live Events) — red bold CALL ALERT badge, Unit A → Unit B detail, dedicated filter checkbox
• index.html (Event Horizon) — call alert row in rate meter (red gradient), red background streak
• omnitrunker.html — red CALL ALERT badge, target unit in TG columns, filterable
• omnitrunker-classic.html — same as omnitrunker
• irc-radio-live.html — 🚨 CALL ALERT: UnitA → UnitB posted to *status (no talkgroup, so goes to system status channel)

Test plan

• Merge Add P25 Call Alert (TSBK 0x1F) decoding TrunkRecorder/trunk-recorder#1126
• Merge Add unit_call_alert for P25 Call Alert (TSBK 0x1F) messages TrunkRecorder/tr-plugin-mqtt#8
• Confirm tr/units/{sys}/call_alert messages arrive at MQTT broker
• Confirm rows appear in unit_events with metadata_json.target_unit
• Red CALL ALERT badge visible in Live Events
• Event Horizon rate meter shows call alert bar
• Omnitrunker shows badge with target unit in TG column
• IRC *status receives alert message

🤖 Generated with Claude Code

[LumenPrima]

Code review

Found 1 issue:

1. Dedup key does not include TargetUnit, so simultaneous call alerts from the same source unit to different targets within the 10-second window collapse into one event — the second alert is silently dropped from the DB and SSE stream. Since call alerts carry no talkgroup (Tgid is always 0), the key {SystemID, UnitID, EventType=call_alert, Tgid=0} is identical for every alert initiated by the same unit, regardless of who is being paged. TargetUnit should be added to unitDedupKey for this event type.

tr-engine/internal/ingest/handler_units.go

Lines 84 to 94 in cc84324

	{
	dk := unitDedupKey{
	SystemID: identity.SystemID,
	UnitID: data.Unit,
	EventType: eventType,
	Tgid: data.Talkgroup,
	}
	if _, loaded := p.unitEventDedup.LoadOrStore(dk, time.Now()); loaded {
	isDup = true
	}
	}

🤖 Generated with Claude Code

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