Enable r2d2 feature for diesel and clarify error types

Added the 'r2d2' feature to the diesel dependency in rustapi-extras to ensure r2d2 integration is available. Updated error handling in DieselPoolBuilder to explicitly use r2d2::Error, improving type clarity.

Author: Tuntii

Cargo.lock

@@ -41,7 +41,7 @@ dashmap = { version = "6.0", optional = true }
 sqlx = { version = "0.8", optional = true, default-features = false }
 
 # Diesel (feature-gated)
-diesel = { version = "2.2", optional = true, default-features = false }
+diesel = { version = "2.2", optional = true, default-features = false, features = ["r2d2"] }
 r2d2 = { version = "0.8", optional = true }
 
 # Configuration (feature-gated)

crates/rustapi-extras/Cargo.toml

@@ -217,7 +217,7 @@ impl DieselPoolBuilder {
 
         builder
             .build(manager)
-            .map_err(|e| DieselPoolError::Pool(e.to_string()))
+            .map_err(|e: r2d2::Error| DieselPoolError::Pool(e.to_string()))
     }
 
     /// Build a MySQL connection pool
@@ -255,7 +255,7 @@ impl DieselPoolBuilder {
 
         builder
             .build(manager)
-            .map_err(|e| DieselPoolError::Pool(e.to_string()))
+            .map_err(|e: r2d2::Error| DieselPoolError::Pool(e.to_string()))
     }
 
     /// Build a SQLite connection pool
@@ -295,7 +295,7 @@ impl DieselPoolBuilder {
 
         builder
             .build(manager)
-            .map_err(|e| DieselPoolError::Pool(e.to_string()))
+            .map_err(|e: r2d2::Error| DieselPoolError::Pool(e.to_string()))
     }
 
     /// Create a health check for a PostgreSQL pool