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/storage_service.h

@@ -32,6 +32,8 @@ class StorageService : public Service {
     // paused (over 90 % full, or no card) or if too much is already waiting. A Capture (or a Track,
     // something the user started) keeps going past 90 %, until the card is full.
     void appendLine(const std::string& path, const std::string& line, bool capture = false);
+    // The same, for binary files (a pcap Capture): the bytes as they are, no newline.
+    void appendBytes(const std::string& path, const std::string& bytes, bool capture = false);
     uint32_t droppedLines() const { return dropped_; }
 
     // Storage Clean-up: list every file of every category, then delete a selection.
@@ -73,7 +75,12 @@ class StorageService : public Service {
     mutable SemaphoreHandle_t lock_ = nullptr;
 
     // Shared with other tasks, guarded by lock_.
-    std::deque<std::pair<std::string, std::string>> pending_;
+    struct Pending {
+        std::string path, data;
+        bool newline;
+    };
+    std::deque<Pending> pending_;
+    void append(const std::string& path, const std::string& data, bool capture, bool newline);
     size_t pendingBytes_ = 0;
     uint32_t dropped_ = 0;
     bool listingRequested_ = false;