Switch Nym WS transport to nym-client's binary protocol, drop second base64 layer

Client.Send now speaks nym-client's native binary websocket protocol
(tag || recipient || conn_id || data_len || data) instead of wrapping
the ciphertext in a JSON text message, which required base64-encoding
it a second time on top of the browser's own base64 layer.

The reader's self-address query also switched to the binary protocol:
nym-client picks text-vs-binary for every later "received" push based
on the format of the last request seen on a connection, so leaving the
reader in JSON/text mode would have made nym-client run a lossy UTF-8
conversion over the now-unencoded binary payload, corrupting it. Fixed
the binary Received-frame parsing along the way (previous code assumed
a fixed 16-byte tag with no length prefix, which never matched the real
protocol and was never exercised while the connection stayed text-mode).

Verified end-to-end against the real embedded nym-client 1.1.76 binary,
with the exact wire format cross-checked against upstream nym source at
the pinned build commit.

1 files changed, 12 insertions, 12 deletions

diff --git a/internal/relay/relay.go b/internal/relay/relay.go
index 9a17fab..54d4571 100644
--- a/internal/relay/relay.go
+++ b/internal/relay/relay.go
@@ -8,18 +8,18 @@ import (
 	"nymdrop/internal/nym"
 )
 
-// Two base64 layers stack between the raw file and the wire: the client
-// base64-encodes the file into the plaintext before encrypting (see
-// static/crypto.js, ~4/3 inflation), then nym.Client.Send base64-encodes
-// the whole ciphertext again to embed it in the JSON message sent to the
-// local nym-client over its control WebSocket (~4/3 again). The combined
-// ~1.78x inflation is bounded above by nym-client's own hardcoded 16MB
-// WebSocket message limit, not by anything in this codebase, so this
-// buffer (and the nginx/http-layer cap) must stay well under 16MB / 1.78
-// once the second layer is applied. 11MB here keeps the second-layer
-// base64 (~14.7MB) with real margin below the 16MB nym-client ceiling,
-// which works out to a safe raw file size of roughly 8MB, not 10MB.
-const maxPayloadBytes = 11 * 1024 * 1024 // 11 MB wire (first base64 layer only)
+// One base64 layer remains between the raw file and the wire: the browser
+// client base64-encodes the file into the plaintext before encrypting (see
+// static/crypto.js, ~4/3 inflation). nym.Client.Send used to base64-encode
+// the whole ciphertext a second time to embed it in a JSON message for the
+// local nym-client's WebSocket control channel; it now sends the raw bytes
+// via nym-client's binary protocol instead, so that second inflation is
+// gone. The remaining ~4/3 inflation is still bounded above by nym-client's
+// own hardcoded 16MB WebSocket message limit. This cap (11MB) predates the
+// binary-protocol fix and still reflects the old two-layer math (safe raw
+// file size ~8MB) — raising it towards the ~16MB/1.33 headroom the fix
+// actually unlocked is a deliberate follow-up, not done here.
+const maxPayloadBytes = 11 * 1024 * 1024 // 11 MB wire
 
 // Relay receives ciphertext and forwards it through Nym. Nothing is written to disk.
 type Relay struct {