[feat](trx-server): gzip-compress history replay blob

Add flate2 dependency and a new AUDIO_MSG_HISTORY_COMPRESSED (0x0a)
wire type. The server gzip-compresses the full history blob before
sending; JSON history compresses ~10-20x so both transfer size and
client wait time drop significantly. The client decompresses and
dispatches sub-messages from the embedded framed stream. MAX_PAYLOAD_SIZE
is kept at 1 MB for normal messages; a separate 16 MB limit is applied
only to the compressed history type.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-server/Cargo.toml

@@ -13,6 +13,7 @@ default = ["soapysdr"]
 soapysdr = ["trx-backend/soapysdr"]
 
 [dependencies]
+flate2 = { workspace = true }
 tokio = { workspace = true, features = ["full"] }
 tokio-serial = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
@@ -37,4 +38,4 @@ trx-cw = { path = "../decoders/trx-cw" }
 trx-decode-log = { path = "../decoders/trx-decode-log" }
 trx-ft8 = { path = "../decoders/trx-ft8" }
 trx-wspr = { path = "../decoders/trx-wspr" }
-trx-protocol = { path = "../trx-protocol" }
+trx-protocol = { path = "../trx-protocol" }