chore: add volc-visual-sdk dependency (signer only, no blocking)

Cargo.lock

@@ -431,6 +431,7 @@ dependencies = [
  "tracing-test",
  "url",
  "uuid",
+ "volc-visual-sdk",
  "wiremock",
 ]
 
@@ -3571,6 +3572,20 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
+[[package]]
+name = "volc-visual-sdk"
+version = "0.1.0"
+dependencies = [
+ "chrono",
+ "hex",
+ "hmac",
+ "serde",
+ "serde_json",
+ "sha2",
+ "thiserror 1.0.69",
+ "url",
+]
+
 [[package]]
 name = "want"
 version = "0.3.1"

Cargo.toml

@@ -84,6 +84,12 @@ mime_guess = "2"
 open-agent-sdk = { path = "../open-agent-sdk-rust" }
 async-trait = "0.1"
 
+# Volcengine Visual (CV) Signature V4 signer for the Jimeng provider. Used as a
+# pure request signer only (build_signed_request) — the blocking reqwest HTTP
+# client is disabled (default-features = false) so requests go out over the
+# shared async reqwest client in AppState instead.
+volc-visual-sdk = { path = "../volc-visual-sdk", default-features = false }
+
 [dev-dependencies]
 rstest = "0.24"
 wiremock = "0.6"