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/view/chat.rs

@@ -0,0 +1,134 @@
+use ratatui::layout::Rect;
+use ratatui::style::{Style, Modifier};
+use ratatui::text::{Line, Span};
+use ratatui::widgets::{Block, Borders, Paragraph, Wrap};
+use ratatui::Frame;
+use super::theme::Theme;
+
+fn _role_name(role: &crate::dto::chat::message::Role) -> &'static str {
+    match role {
+        crate::dto::chat::message::Role::User => "User",
+        crate::dto::chat::message::Role::Assistant => "Assistant",
+        crate::dto::chat::message::Role::System => "System",
+        crate::dto::chat::message::Role::Tool => "Tool",
+    }
+}
+
+fn role_badge(role: &crate::dto::chat::message::Role) -> &'static str {
+    match role {
+        crate::dto::chat::message::Role::User => "YOU",
+        crate::dto::chat::message::Role::Assistant => "AI ",
+        crate::dto::chat::message::Role::System => "SYS",
+        crate::dto::chat::message::Role::Tool => "TOOL",
+    }
+}
+
+fn format_timestamp(ts: i64) -> String {
+    if ts <= 0 { return "".to_string(); }
+    let secs = ts / 1000;
+    let mins = (secs / 60) % 60;
+    let hrs = (secs / 3600) % 24;
+    format!("{:02}:{:02}", hrs, mins)
+}
+
+pub fn draw_chat(frame: &mut Frame, area: Rect, state: &crate::app::state::rest::AppStateRest) {
+    let messages = &state.transcript_cache.messages;
+    let scroll_offset = state.scroll.offset;
+    let max_visible = (area.height as usize).saturating_sub(3);
+
+    let mut display_lines: Vec<Line> = Vec::new();
+
+    if scroll_offset > 0 {
+        let above = messages.len().saturating_sub(scroll_offset + max_visible).saturating_sub(1);
+        if above > 0 {
+            display_lines.push(Line::from(Span::styled(
+                format!("  ↑ {} more messages above", above),
+                Style::default().fg(Theme::DIM),
+            )));
+        }
+    }
+
+    let iter_start = if scroll_offset + max_visible >= messages.len() {
+        0usize
+    } else {
+        messages.len().saturating_sub(scroll_offset + max_visible)
+    };
+
+    for msg in messages.iter().skip(iter_start).take(scroll_offset + max_visible) {
+        let role_color = match msg.role {
+            crate::dto::chat::message::Role::User => Theme::ROLE_USER,
+            crate::dto::chat::message::Role::Assistant => Theme::ROLE_ASSISTANT,
+            crate::dto::chat::message::Role::System => Theme::ROLE_SYSTEM,
+            crate::dto::chat::message::Role::Tool => Theme::ROLE_TOOL,
+        };
+        let prefix = match msg.role {
+            crate::dto::chat::message::Role::User => ">",
+            crate::dto::chat::message::Role::Assistant => "•",
+            crate::dto::chat::message::Role::System => "#",
+            crate::dto::chat::message::Role::Tool => "→",
+        };
+
+        let ts_str = format_timestamp(msg.timestamp);
+        let badge = role_badge(&msg.role);
+        let time_display = if ts_str.is_empty() { String::new() } else { format!(" [{}]", ts_str) };
+
+        let header = Line::from(vec![
+            Span::styled(
+                format!(" {} ", badge),
+                Style::default().fg(Theme::BG).bg(role_color).add_modifier(Modifier::BOLD),
+            ),
+            Span::styled(
+                time_display,
+                Style::default().fg(Theme::DIM),
+            ),
+        ]);
+
+        let content_str = if msg.content.is_empty() {
+            "(streaming...)".to_string()
+        } else {
+            msg.content.clone()
+        };
+        let content_line = Line::from(vec![
+            Span::styled(format!("{} ", prefix), Style::default().fg(role_color)),
+            Span::styled(content_str, Style::default().fg(Theme::TEXT)),
+        ]);
+
+        display_lines.push(header);
+        display_lines.push(content_line);
+        display_lines.push(Line::from(Span::raw("")));
+    }
+
+    if messages.len() > scroll_offset + max_visible {
+        let below = messages.len().saturating_sub(scroll_offset + max_visible);
+        display_lines.push(Line::from(Span::styled(
+            format!("  ↓ {} more messages below", below),
+            Style::default().fg(Theme::DIM),
+        )));
+    }
+
+    let mut title = String::from(" Chat ");
+    if !messages.is_empty() {
+        title.push_str(&format!("[{} msgs]", messages.len()));
+    }
+
+    let block = Block::default()
+        .borders(Borders::ALL)
+        .border_style(Style::default().fg(Theme::BORDER))
+        .title(title);
+
+    let total = display_lines.len();
+    let end_idx = total.saturating_sub(scroll_offset);
+    let start_idx = end_idx.saturating_sub(max_visible);
+    let end_idx = end_idx.min(total);
+    let visible: Vec<Line> = if start_idx < end_idx {
+        display_lines[start_idx..end_idx].to_vec()
+    } else {
+        Vec::new()
+    };
+
+    let paragraph = Paragraph::new(visible)
+        .block(block)
+        .wrap(Wrap { trim: false });
+
+    frame.render_widget(paragraph, area);
+}