M3 step 4: the LoRa Scanner App, Sniffer and Captures

The Sniffer lists packets newest first (time, RSSI, SNR, and for
Meshtastic the sender, receiver and hops), with the clear header and a
hex dump on Enter (Q96); `p` picks an EU868 preset, kept in Settings
(Q95). `c` starts a Capture: pcap with LoRaTap in /captures/lora, its own
Clean-up category, recorded by a small Service so it carries on with the
App closed (Q97, Q100). The Status Bar shows L while listening, bright on
each packet, and CAP while capturing (Q101). StorageService gains raw
appends for binary files. Debug Builds get `lora inject` to test all of
this with no transmitter in range: a Capture made on the device reads
back in TShark field for field.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/services/lora_capture_service.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <string>
+
+#include "event_bus.h"
+#include "service.h"
+#include "services/clock_service.h"
+#include "services/radio_service.h"
+#include "services/storage_service.h"
+
+namespace roro {
+
+// A LoRa Sniffer Capture (CONTEXT.md: Capture; M3, Q97): every packet the radio receives, as pcap
+// with LoRaTap headers, in /captures/lora/. Started and stopped by hand; keeps the radio listening
+// and keeps recording whatever App is open (Q100).
+class LoraCaptureService : public Service {
+   public:
+    LoraCaptureService(RadioService& radio, StorageService& storage, ClockService& clock, EventBus& bus)
+        : radio_(radio), storage_(storage), clock_(clock), bus_(bus) {}
+    const char* name() const override { return "lora-capture"; }
+    uint32_t tickIntervalMs() const override { return 200; }
+    void tick(uint32_t nowMs) override;
+
+    std::string start(uint32_t nowMs);  // why it can't, or ""
+    void stop();
+    bool capturing() const { return !path_.empty(); }
+    const std::string& path() const { return path_; }
+    uint32_t packets() const { return packets_; }
+
+   private:
+    void notify(const std::string& text);
+
+    RadioService& radio_;
+    StorageService& storage_;
+    ClockService& clock_;
+    EventBus& bus_;
+    std::string path_;
+    uint32_t written_ = 0;  // the radio's seq last written
+    uint32_t packets_ = 0;
+    int64_t startUtc_ = 0;  // the Clock and millis() when it started: packet times follow from both
+    uint32_t startMs_ = 0;
+};
+
+}  // namespace roro