feat: disable capabilities by model provider (#19442)

## Why

Unsupported features must fail closed and Codex must not expose
OpenAI-hosted fallback paths when the active provider cannot support
them. In practice, Bedrock should not surface app connectors, MCP
servers, tool search/suggestions, image generation, web search, or JS
REPL until those paths are explicitly supported for that provider.

This PR moves that decision into provider-owned capability metadata
instead of scattering Bedrock-specific checks across callers.

## What changed

- Adds `ProviderCapabilities` to `codex-model-provider`, with default
support for existing providers and a Bedrock override that disables
unsupported launch surfaces.
- Adds `ToolCapabilityBounds` to `codex-tools` so provider capability
limits can clamp otherwise-enabled tool config.
- Applies capability bounds when building session and review-thread tool
config.
- Routes MCP/app connector configuration through
`McpManager::mcp_config`, which filters configured MCP servers and app
connectors based on the active provider.
- Updates app-server MCP list/read paths to use the filtered MCP config.
- Adds coverage for default provider capabilities, Bedrock disabled
capabilities, and optional tool-surface clamping.

## Testing

built locally and verified that bedrock responses api now return without
errors calling unsupported tools.

codex-rs/model-provider/src/amazon_bedrock/mod.rs

@@ -21,6 +21,7 @@ use codex_protocol::openai_models::ModelsResponse;
 use crate::provider::ModelProvider;
 use crate::provider::ProviderAccountResult;
 use crate::provider::ProviderAccountState;
+use crate::provider::ProviderCapabilities;
 use auth::resolve_provider_auth;
 use auth::resolve_region;
 pub(crate) use catalog::static_model_catalog;
@@ -55,6 +56,14 @@ impl ModelProvider for AmazonBedrockModelProvider {
         &self.info
     }
 
+    fn capabilities(&self) -> ProviderCapabilities {
+        ProviderCapabilities {
+            namespace_tools: false,
+            image_generation: false,
+            web_search: false,
+        }
+    }
+
     fn auth_manager(&self) -> Option<Arc<AuthManager>> {
         None
     }
@@ -116,4 +125,20 @@ mod tests {
             "https://bedrock-mantle.eu-central-1.api.aws/v1"
         );
     }
+
+    #[test]
+    fn capabilities_disable_unsupported_launch_features() {
+        let provider = AmazonBedrockModelProvider::new(
+            ModelProviderInfo::create_amazon_bedrock_provider(/*aws*/ None),
+        );
+
+        assert_eq!(
+            provider.capabilities(),
+            ProviderCapabilities {
+                namespace_tools: false,
+                image_generation: false,
+                web_search: false,
+            }
+        );
+    }
 }