fix(mesh): Meshtastic 3ccc pkc_capable pill + Sideband image interop + critical CBOR wire-bloat fix

Merges in the meshtastic agent's now-finished work alongside this session's
continuation: stock-peer (3ccc) PKI-capability is now stamped through
get_contacts -> refresh_contacts -> MeshPeer.pkc_capable, so a directed DM to/from
a PKC-capable stock Meshtastic peer correctly shows the E2E pill on the Sent row,
not just received messages. Confirmed live: .198 sees "Meshtastic 3ccc" with
pkc_capable=true.

Also fixes two real interop/correctness bugs found while live-testing the
Reticulum <-> Sideband link:
  - Receive: the daemon only ever read LXMF's plain-text content, silently
    dropping native FIELD_IMAGE/FIELD_FILE_ATTACHMENTS fields — a stock
    Sideband/NomadNet photo vanished into a blank-space message. Now decoded
    into the same ContentInline typed envelope our own attachments use.
  - Send: images to a non-archy (stock) peer now use native LXMF FIELD_IMAGE
    instead of our own opaque CBOR wire format, which Sideband can't decode.
  - Root cause of a garbled MC-chunk-fragment bug: TypedEnvelope.v/.sig (the
    OUTER wrapper every message type uses) serialized raw bytes as a CBOR
    array-of-integers instead of a native byte string, bloating every
    message on the wire ~2-3.5x — enough to push even a tiny ReadReceipt
    over the 140-byte single-frame chunking threshold. Root-caused by
    reading ciborium's deserializer source directly (deserialize_bytes only
    works within its internal scratch buffer; deserialize_byte_buf streams
    unbounded).

Frontend: consolidated the attach/record buttons into a single animated "+"
menu (was overflowing the compose row).

857/857 tests pass. Verified live across all 5 deploy-roster nodes.

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

core/archipelago/src/mesh/meshtastic.rs

@@ -691,7 +691,20 @@ impl MeshtasticDevice {
                 }
             }
         }
-        Ok(self.contacts.values().cloned().collect())
+        // Stamp E2E capability per contact from `peer_pubkeys` (the real
+        // Curve25519 keys learned from NodeInfo / inbound PKC packets), keyed by
+        // node-num — which is exactly the contacts map key. This lets the send
+        // path mark a Sent DM to ANY PKC-capable peer (e.g. a stock device that
+        // shared its key) as E2E, not just archipelago peers.
+        Ok(self
+            .contacts
+            .iter()
+            .map(|(num, c)| {
+                let mut c = c.clone();
+                c.pkc_capable = self.peer_is_pkc_capable(*num);
+                c
+            })
+            .collect())
     }
 
     pub async fn reset_contact_path(&mut self, _pubkey: &[u8; 32]) -> Result<()> {
@@ -740,10 +753,9 @@ impl MeshtasticDevice {
     /// Whether we've learned `node_num`'s real PKI (Curve25519) key — from a
     /// NodeInfo `public_key` or an inbound PKC DM — meaning the firmware can
     /// deliver DMs to/from it end-to-end encrypted instead of falling back to
-    /// the channel PSK. Driver-internal for now; lets a future mesh-tab badge
-    /// distinguish a true E2E DM from a channel-encrypted one without changing
-    /// the shared device interface (which would break meshcore hot-swap).
-    #[allow(dead_code)] // seam: consumed when the mesh-tab E2E badge lands
+    /// the channel PSK. Consumed by `get_contacts` to stamp `ParsedContact
+    /// .pkc_capable`, so the send path can mark a Sent DM to any PKC-capable
+    /// peer as E2E (not just archipelago peers).
     pub fn peer_is_pkc_capable(&self, node_num: u32) -> bool {
         self.peer_pubkeys
             .get(&node_num)
@@ -921,6 +933,8 @@ impl MeshtasticDevice {
                     contact_type: 1,
                     path_len: 0xff,
                     flags: 0,
+                    // Stamped fresh from `peer_pubkeys` in `get_contacts`.
+                    pkc_capable: false,
                 },
             );
         }
@@ -1008,6 +1022,8 @@ fn packet_to_inbound_frame(
         contact_type: 1,
         path_len: 0xff,
         flags: 0,
+        // Stamped fresh from `peer_pubkeys` in `get_contacts`.
+        pkc_capable: false,
     });
 
     // Channel broadcast (e.g. the default public LongFast channel, or any other