feat(proxy): add scoped proxy configuration and docs runbooks

- add scope-aware proxy schema and runtime wiring for providers/channels/tools

- add agent callable proxy_config tool for fast proxy setup

- standardize docs system with index, template, and playbooks

src/providers/openai.rs

@@ -10,7 +10,6 @@ use serde::{Deserialize, Serialize};
 pub struct OpenAiProvider {
     base_url: String,
     credential: Option<String>,
-    client: Client,
 }
 
 #[derive(Debug, Serialize)]
@@ -148,11 +147,6 @@ impl OpenAiProvider {
                 .map(|u| u.trim_end_matches('/').to_string())
                 .unwrap_or_else(|| "https://api.openai.com/v1".to_string()),
             credential: credential.map(ToString::to_string),
-            client: Client::builder()
-                .timeout(std::time::Duration::from_secs(120))
-                .connect_timeout(std::time::Duration::from_secs(10))
-                .build()
-                .unwrap_or_else(|_| Client::new()),
         }
     }
 
@@ -254,6 +248,10 @@ impl OpenAiProvider {
 
         ProviderChatResponse { text, tool_calls }
     }
+
+    fn http_client(&self) -> Client {
+        crate::config::build_runtime_proxy_client_with_timeouts("provider.openai", 120, 10)
+    }
 }
 
 #[async_trait]
@@ -290,7 +288,7 @@ impl Provider for OpenAiProvider {
         };
 
         let response = self
-            .client
+            .http_client()
             .post(format!("{}/chat/completions", self.base_url))
             .header("Authorization", format!("Bearer {credential}"))
             .json(&request)
@@ -331,7 +329,7 @@ impl Provider for OpenAiProvider {
         };
 
         let response = self
-            .client
+            .http_client()
             .post(format!("{}/chat/completions", self.base_url))
             .header("Authorization", format!("Bearer {credential}"))
             .json(&native_request)
@@ -358,7 +356,7 @@ impl Provider for OpenAiProvider {
 
     async fn warmup(&self) -> anyhow::Result<()> {
         if let Some(credential) = self.credential.as_ref() {
-            self.client
+            self.http_client()
                 .get(format!("{}/models", self.base_url))
                 .header("Authorization", format!("Bearer {credential}"))
                 .send()