feat(workspace): initialize Rust workspace structure for v2

Set up Cargo workspace with initial crates:
- cli: main application entry point with chat streaming tests
- config: configuration management
- llm/ollama: Ollama client integration with NDJSON support

Includes .gitignore for Rust and JetBrains IDEs.

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

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

crates/config/src/lib.rs

@@ -0,0 +1,55 @@
+use directories::ProjectDirs;
+use figment::{
+    Figment,
+    providers::{Env, Format, Serialized, Toml},
+};
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Settings {
+    #[serde(default = "default_ollama_url")]
+    pub ollama_url: String,
+    #[serde(default = "default_model")]
+    pub model: String,
+    #[serde(default = "default_mode")]
+    pub mode: String, // "plan" (read-only) for now
+}
+
+fn default_ollama_url() -> String {
+    "http://localhost:11434".into()
+}
+fn default_model() -> String {
+    "qwen2.5".into()
+}
+fn default_mode() -> String {
+    "plan".into()
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Self {
+            ollama_url: default_ollama_url(),
+            model: default_model(),
+            mode: default_mode(),
+        }
+    }
+}
+
+pub fn load_settings(project_root: Option<&str>) -> Result<Settings, figment::Error> {
+    let mut fig = Figment::from(Serialized::defaults(Settings::default()))
+        .merge(Env::prefixed("CODE_").split("__"));
+
+    // User file: ~/.config/owlen/config.toml
+    if let Some(pd) = ProjectDirs::from("dev", "owlibou", "owlen") {
+        let user = pd.config_dir().join("config.toml");
+        fig = fig.merge(Toml::file(user));
+    }
+
+    // Project file: <root>/.owlen.toml
+    if let Some(root) = project_root {
+        fig = fig.merge(Toml::file(PathBuf::from(root).join(".owlen.toml")));
+    }
+
+    fig.extract()
+}