feat(mesh): Reticulum LoRa hardware gates pass + RNS Resource transfer + image/voice attachments

Phase 0 gates #2/#3 (two-node LXMF-over-LoRa, external Sideband interop) passed
on real hardware (.116's flashed Heltec V3 RNode <-> a phone-flashed RNode running
Sideband) — RNS announce, encrypted DM round-trip, and contact binding all verified
live. Fixed two bugs found in the process: the Reticulum send path wasn't stamping
outbound messages as E2E despite LXMF being unconditionally encrypted, and the
per-message transport pill collapsed Meshcore/Meshtastic into one generic "lora"
color instead of distinguishing the three radio transports.

Built on top of that link: a Columba-style image/file send experience —
compression-quality presets with a real transfer-time estimate (mesh.transport-advice,
now device-throughput-aware), receive-side thumbnail previews + auto-render for
already-local attachments, and async voice messages, all reusing the existing
ContentRef/ContentInline attachment pipeline. The headline addition is genuine RNS
Resource transfer support (daemon-side RNS.Link + RNS.Resource, Rust-side
send_resource/resource_recv plumbing, a new "resource-mesh" transport-advice tier)
so compressed photos up to 2MB now actually transfer over LoRa for Reticulum peers
instead of always falling back to Tor past the small inline-chunk cap.

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

core/archipelago/src/api/handler/blob.rs

@@ -48,6 +48,17 @@ impl ApiHandler {
             .get("x-blob-filename")
             .and_then(|v| v.to_str().ok())
             .map(|s| s.to_string());
+        // Optional caller-supplied thumbnail (small, base64) — e.g. the mesh
+        // chat's image-quality picker generates a tiny client-side preview so
+        // a ContentRef receiver can render something before fetching the full
+        // blob. Best-effort: a malformed header is just ignored, not fatal.
+        let thumb_bytes = headers
+            .get("x-blob-thumb")
+            .and_then(|v| v.to_str().ok())
+            .and_then(|b64| {
+                use base64::{engine::general_purpose::STANDARD, Engine as _};
+                STANDARD.decode(b64).ok()
+            });
 
         let bytes = body.to_vec();
         // Uploads through /api/blob come from the node owner's session and
@@ -55,7 +66,7 @@ impl ApiHandler {
         // pictures, banners). Store them public so `/blob/<cid>` serves
         // without a capability check — external Nostr clients fetching a
         // kind-0 `picture` URL have no cap and can't get one.
-        match store.put(&bytes, &mime, filename, None, true).await {
+        match store.put(&bytes, &mime, filename, thumb_bytes, true).await {
             Ok(meta) => {
                 let exp =
                     (chrono::Utc::now().timestamp() as u64) + crate::blobs::DEFAULT_CAP_TTL_SECS;