feat(phase10): complete MCP-only architecture migration

This commit completes Phase 10 of the MCP migration by removing all
direct provider usage from CLI/TUI and enforcing MCP-first architecture.

## Changes

### Core Architecture
- **main.rs**: Replaced OllamaProvider with RemoteMcpClient
  - Uses MCP server configuration from config.toml if available
  - Falls back to auto-discovery of MCP LLM server binary
- **agent_main.rs**: Unified provider and MCP client to single RemoteMcpClient
  - Simplifies initialization with Arc::clone pattern
  - All LLM communication now goes through MCP protocol

### Dependencies
- **Cargo.toml**: Removed owlen-ollama dependency from owlen-cli
  - CLI no longer knows about Ollama implementation details
  - Clean separation: only MCP servers use provider crates internally

### Tests
- **agent_tests.rs**: Updated all tests to use RemoteMcpClient
  - Replaced OllamaProvider::new() with RemoteMcpClient::new()
  - Updated test documentation to reflect MCP requirements
  - All tests compile and run successfully

### Examples
- **Removed**: custom_provider.rs, basic_chat.rs (deprecated)
- **Added**: mcp_chat.rs - demonstrates recommended MCP-based usage
  - Shows how to use RemoteMcpClient for LLM interactions
  - Includes model listing and chat request examples

### Cleanup
- Removed outdated TODO about MCP integration (now complete)
- Updated comments to reflect current MCP architecture

## Architecture

```
CLI/TUI → RemoteMcpClient (impl Provider)
          ↓ MCP Protocol (STDIO/HTTP/WS)
          MCP LLM Server → OllamaProvider → Ollama
```

## Benefits
- ✅ Clean separation of concerns
- ✅ CLI is protocol-agnostic (only knows MCP)
- ✅ Easier to add new LLM backends (just implement MCP server)
- ✅ All tests passing
- ✅ Full workspace builds successfully

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

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

crates/owlen-cli/src/main.rs

@@ -2,8 +2,10 @@
 
 use anyhow::Result;
 use clap::Parser;
-use owlen_core::{mode::Mode, session::SessionController, storage::StorageManager};
-use owlen_ollama::OllamaProvider;
+use owlen_core::{
+    mcp::remote_client::RemoteMcpClient, mode::Mode, session::SessionController,
+    storage::StorageManager, Provider,
+};
 use owlen_tui::tui_controller::{TuiController, TuiRequest};
 use owlen_tui::{config, ui, AppState, ChatApp, Event, EventHandler, SessionEvent};
 use std::io;
@@ -21,7 +23,7 @@ use ratatui::{prelude::CrosstermBackend, Terminal};
 /// Owlen - Terminal UI for LLM chat
 #[derive(Parser, Debug)]
 #[command(name = "owlen")]
-#[command(about = "Terminal UI for LLM chat with Ollama", long_about = None)]
+#[command(about = "Terminal UI for LLM chat via MCP", long_about = None)]
 struct Args {
     /// Start in code mode (enables all tools)
     #[arg(long, short = 'c')]
@@ -44,21 +46,16 @@ async fn main() -> Result<()> {
     let mut cfg = config::try_load_config().unwrap_or_default();
     // Disable encryption for CLI to avoid password prompts in this environment.
     cfg.privacy.encrypt_local_data = false;
-    // Determine provider configuration
-    let provider_name = cfg.general.default_provider.clone();
-    let provider_cfg = config::ensure_provider_config(&mut cfg, &provider_name).clone();
-    let provider_type = provider_cfg.provider_type.to_ascii_lowercase();
-    if provider_type != "ollama" && provider_type != "ollama-cloud" {
-        anyhow::bail!(
-            "Unsupported provider type '{}' configured for provider '{}'",
-            provider_cfg.provider_type,
-            provider_name,
-        );
-    }
-    let provider = Arc::new(OllamaProvider::from_config(
-        &provider_cfg,
-        Some(&cfg.general),
-    )?);
+
+    // Create MCP LLM client as the provider (replaces direct OllamaProvider usage)
+    let provider: Arc<dyn Provider> = if let Some(mcp_server) = cfg.mcp_servers.first() {
+        // Use configured MCP server if available
+        Arc::new(RemoteMcpClient::new_with_config(mcp_server)?)
+    } else {
+        // Fall back to default MCP LLM server discovery
+        Arc::new(RemoteMcpClient::new()?)
+    };
+
     let storage = Arc::new(StorageManager::new().await?);
     let controller =
         SessionController::new(provider, cfg, storage.clone(), tui_controller, false).await?;