perf: reduce binary sizes from 15M/11M to 3.8M/5.5M

- Add [profile.release]: opt-level=z, lto=true, strip=true, codegen-units=1, panic=abort
- Replace vendored openssl (~5MB) with ed25519-dalek (pure Rust, ~100KB)
- Feature-gate deps: server (actix, chrono) vs pusher (zmq, reqwest, ed25519-dalek)
- Remove unused confy dependency
- bal-pusher: 15M -> 3.8M (-75%)
- bal-server: 11M -> 5.5M (-50%)

Cargo.toml

@@ -4,33 +4,48 @@ version = "0.3.1"
 edition = "2024"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[features]
+default = ["server"]
+server = ["dep:actix-web", "dep:actix-governor", "dep:actix-rt", "dep:chrono", "dep:hex-conservative"]
+pusher = ["dep:zmq", "dep:reqwest", "dep:byteorder", "dep:base64", "dep:ed25519-dalek"]
+
 [dependencies]
-base64 = 		{ version = "0.22.1" }
 bs58 = 			{ version = "0.4.0" }
 bytes = 		{ version = "1.2" }
 bitcoin = 		{ version = "0.32.5" }
 bitcoincore-rpc = 	{ version = "0.19.0" }
 bitcoincore-rpc-json = 	{ version = "0.19.0" }
-byteorder = 		{ version = "1.5.0" }
-confy = 		{ version = "0.6.1" }
-chrono = 		{ version = "0.4.40" }
 env_logger = 		{ version = "0.11.5" }
 hex = 			{ version = "0.4.3" }
-hex-conservative = 	{ version = "0.1.1" }
-actix-web = 		{ version = "4.9.0" }
-actix-governor = 	{ version = "0.6.0" }
 log = 			{ version = "0.4.21" }
-openssl = 		{ version = "0.10.74", features = ["vendored"] }
-sha2 = 			{ version = "0.10.8" }
 serde = 		{ version = "1.0.152", features = ["derive"] }
 serde_json = 		{ version = "1.0.116" }
 sqlite = 		{ version = "0.34.0" }
 regex = 		{ version = "1.10.4" }
-reqwest = 		{ version = "0.12.24", features = ["json","socks"] }
-actix-rt = 		{ version = "2.10.0" }
 tokio = 		{ version = "1", features = ["rt", "net","macros","rt-multi-thread"] }
 url = 			{ version = "2" }
-zmq = 			{ version = "0.10.0" }
+
+# server-only
+actix-web = 		{ version = "4.9.0", optional = true }
+actix-governor = 	{ version = "0.6.0", optional = true }
+actix-rt = 		{ version = "2.10.0", optional = true }
+chrono = 		{ version = "0.4.40", optional = true }
+hex-conservative = 	{ version = "0.1.1", optional = true }
+
+# pusher-only
+zmq = 			{ version = "0.10.0", optional = true }
+reqwest = 		{ version = "0.12.24", features = ["json","socks"], optional = true }
+byteorder = 		{ version = "1.5.0", optional = true }
+base64 = 		{ version = "0.22.1", optional = true }
+ed25519-dalek = 	{ version = "2", features = ["pem", "pkcs8"], optional = true }
+sha2 = 			{ version = "0.10.8" }
+
+[profile.release]
+opt-level = "z"
+lto = true
+codegen-units = 1
+strip = true
+panic = "abort"
 
 [[bin]]
 name = "bal-server"
@@ -39,4 +54,3 @@ path = "src/bin/bal-server.rs"
 [[bin]]
 name = "bal-pusher"
 path = "src/bin/bal-pusher.rs"
-