fix: resolve all compilation errors and clippy warnings

This commit fixes 12 categories of errors across the codebase:

- Fix owlen-mcp-llm-server build target conflict by renaming lib.rs to main.rs
- Resolve ambiguous glob re-exports in owlen-core by using explicit exports
- Add Default derive to MockMcpClient and MockProvider test utilities
- Remove unused imports from owlen-core test files
- Fix needless borrows in test file arguments
- Improve Config initialization style in mode_tool_filter tests
- Make AgentExecutor::parse_response public for testing
- Remove non-existent max_tool_calls field from AgentConfig usage
- Fix AgentExecutor::new calls to use correct 3-argument signature
- Fix AgentResult field access in agent tests
- Use Debug formatting instead of Display for AgentResult
- Remove unnecessary default() calls on unit structs

All changes ensure the project compiles cleanly with:
- cargo check --all-targets ✓
- cargo clippy --all-targets -- -D warnings ✓
- cargo test --no-run ✓

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

crates/owlen-core/tests/file_server.rs

@@ -1,6 +1,5 @@
-use owlen_core::mcp::client::McpClient;
 use owlen_core::mcp::remote_client::RemoteMcpClient;
-use owlen_core::mcp::McpToolCall;
+use owlen_core::McpToolCall;
 use std::fs::File;
 use std::io::Write;
 use tempfile::tempdir;
@@ -22,7 +21,7 @@ async fn remote_file_server_read_and_list() {
         .join("../..")
         .join("Cargo.toml");
     let build_status = std::process::Command::new("cargo")
-        .args(&["build", "-p", "owlen-mcp-server", "--manifest-path"])
+        .args(["build", "-p", "owlen-mcp-server", "--manifest-path"])
         .arg(manifest_path)
         .status()
         .expect("failed to run cargo build for MCP server");

crates/owlen-core/tests/file_write.rs

@@ -1,13 +1,12 @@
-use owlen_core::mcp::client::McpClient;
 use owlen_core::mcp::remote_client::RemoteMcpClient;
-use owlen_core::mcp::McpToolCall;
+use owlen_core::McpToolCall;
 use tempfile::tempdir;
 
 #[tokio::test]
 async fn remote_write_and_delete() {
     // Build the server binary first
     let status = std::process::Command::new("cargo")
-        .args(&["build", "-p", "owlen-mcp-server"])
+        .args(["build", "-p", "owlen-mcp-server"])
         .status()
         .expect("failed to build MCP server");
     assert!(status.success());
@@ -42,7 +41,7 @@ async fn remote_write_and_delete() {
 async fn write_outside_root_is_rejected() {
     // Build server (already built in previous test, but ensure it exists)
     let status = std::process::Command::new("cargo")
-        .args(&["build", "-p", "owlen-mcp-server"])
+        .args(["build", "-p", "owlen-mcp-server"])
         .status()
         .expect("failed to build MCP server");
     assert!(status.success());

crates/owlen-core/tests/mode_tool_filter.rs

@@ -42,14 +42,16 @@ impl Tool for EchoTool {
 #[tokio::test]
 async fn test_tool_allowed_in_chat_mode() {
     // Build a config where the `echo` tool is explicitly allowed in chat.
-    let mut cfg = Config::default();
-    cfg.modes = ModeConfig {
-        chat: ModeToolConfig {
-            allowed_tools: vec!["echo".to_string()],
-        },
-        code: ModeToolConfig {
-            allowed_tools: vec!["*".to_string()],
+    let cfg = Config {
+        modes: ModeConfig {
+            chat: ModeToolConfig {
+                allowed_tools: vec!["echo".to_string()],
+            },
+            code: ModeToolConfig {
+                allowed_tools: vec!["*".to_string()],
+            },
         },
+        ..Default::default()
     };
     let cfg = Arc::new(Mutex::new(cfg));
 
@@ -70,17 +72,18 @@ async fn test_tool_allowed_in_chat_mode() {
 #[tokio::test]
 async fn test_tool_not_allowed_in_any_mode() {
     // Config that does NOT list `echo` in either mode.
-    let mut cfg = Config::default();
-    cfg.modes = ModeConfig {
-        chat: ModeToolConfig {
-            allowed_tools: vec!["web_search".to_string()],
-        },
-        code: ModeToolConfig {
-            allowed_tools: vec!["*".to_string()], // allow all in code
+    let cfg = Config {
+        modes: ModeConfig {
+            chat: ModeToolConfig {
+                allowed_tools: vec!["web_search".to_string()],
+            },
+            code: ModeToolConfig {
+                // Strict denial - only web_search allowed
+                allowed_tools: vec!["web_search".to_string()],
+            },
         },
+        ..Default::default()
     };
-    // Remove the wildcard for code to simulate strict denial.
-    cfg.modes.code.allowed_tools = vec!["web_search".to_string()];
     let cfg = Arc::new(Mutex::new(cfg));
 
     let ui: Arc<dyn UiController> = Arc::new(NoOpUiController);