Implement chat and markdown views, enhance status bar, and add workflow panel

- Added `chat.rs` for rendering chat messages with timestamps and roles.
- Introduced `markdown.rs` for rendering markdown content with styling.
- Created `status.rs` to display the application status bar with session and message counts.
- Developed `workflow.rs` to show the current workflow status, including tool calls and active jobs.
- Established a `theme.rs` for centralized color management across the UI.
- Updated `mod.rs` to include new modules and manage rendering logic.

src/service/mod.rs

@@ -0,0 +1 @@
+pub mod openrouter;

src/service/openrouter.rs

@@ -0,0 +1,53 @@
+use anyhow::Result;
+use serde_json::Value;
+
+pub struct OpenRouterClient {
+    pub client: reqwest::blocking::Client,
+    pub api_key: String,
+    pub base_url: String,
+    pub model: String,
+}
+
+impl OpenRouterClient {
+    pub fn new(api_key: String, model: String) -> Self {
+        OpenRouterClient {
+            client: reqwest::blocking::Client::new(),
+            api_key,
+            base_url: "https://openrouter.ai/api/v1".to_string(),
+            model,
+        }
+    }
+
+    pub fn chat(&self, messages: &[crate::dto::chat::message::ChatMessage]) -> Result<String> {
+        let req = crate::dto::openrouter::request::ChatRequest {
+            model: self.model.clone(),
+            messages: messages.to_vec(),
+            max_tokens: Some(4096),
+            temperature: Some(0.7),
+            tools: None,
+            stream: Some(false),
+            top_p: None,
+            stop: None,
+        };
+
+        let resp = self.client
+            .post(format!("{}/chat/completions", self.base_url))
+            .header("Authorization", format!("Bearer {}", self.api_key))
+            .header("Content-Type", "application/json")
+            .json(&req)
+            .send()?;
+
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let body = resp.text().unwrap_or_default();
+            anyhow::bail!("OpenRouter API error {}: {}", status, body);
+        }
+
+        let data: Value = resp.json()?;
+        let content = data["choices"][0]["message"]["content"]
+            .as_str()
+            .unwrap_or("")
+            .to_string();
+        Ok(content)
+    }
+}