🐛 Fix tab handling in TUI and propagate CLI custom instructions

Add expand_tabs utility function that converts tab characters to spaces
and strips control characters to prevent visual corruption in diff and
code views. Apply this transformation in code_view and diff_view
components before rendering.

Also fix custom instructions (--instructions flag) not being passed
through to the agent. The temp_instructions config field now properly
flows to build_task_prompt in both execute_capability and streaming
paths, and is applied to Studio's initial commit mode state.

Author: hyperb1iss

src/agents/iris.rs

@@ -666,21 +666,16 @@ Guidelines:
         if capability == "pr" || capability == "review" {
             if gitmoji_enabled {
                 system_prompt.push_str("\n\n=== EMOJI STYLING ===\n");
-                system_prompt.push_str(
-                    "Use emojis to make the output visually scannable and engaging:\n",
-                );
-                system_prompt.push_str(
-                    "- H1 title: ONE gitmoji at the start (✨, 🐛, ♻️, etc.)\n",
-                );
+                system_prompt
+                    .push_str("Use emojis to make the output visually scannable and engaging:\n");
+                system_prompt.push_str("- H1 title: ONE gitmoji at the start (✨, 🐛, ♻️, etc.)\n");
                 system_prompt.push_str(
                     "- Section headers (## headings): Add relevant emojis (🎯 What's New, ⚙️ How It Works, 📋 Commits, ⚠️ Breaking Changes, 🧪 Testing, 📝 Notes)\n",
                 );
-                system_prompt.push_str(
-                    "- Commit list entries: Include the gitmoji from each commit\n",
-                );
-                system_prompt.push_str(
-                    "- Body text: Keep clean - no scattered emojis within prose\n\n",
-                );
+                system_prompt
+                    .push_str("- Commit list entries: Include the gitmoji from each commit\n");
+                system_prompt
+                    .push_str("- Body text: Keep clean - no scattered emojis within prose\n\n");
                 system_prompt.push_str("Choose from this gitmoji list:\n\n");
                 system_prompt.push_str(&crate::gitmoji::get_gitmoji_list());
             } else if is_conventional {

src/agents/setup.rs

@@ -244,8 +244,12 @@ impl IrisAgentService {
         // Create the agent
         let mut agent = self.create_agent()?;
 
-        // Build task prompt with context information (no custom instructions)
-        let task_prompt = Self::build_task_prompt(capability, &context, None);
+        // Build task prompt with context information and any custom instructions from config
+        let task_prompt = Self::build_task_prompt(
+            capability,
+            &context,
+            self.config.temp_instructions.as_deref(),
+        );
 
         // Execute the task
         agent.execute_task(capability, &task_prompt).await
@@ -424,7 +428,11 @@ impl IrisAgentService {
         F: FnMut(&str, &str) + Send,
     {
         let mut agent = self.create_agent()?;
-        let task_prompt = Self::build_task_prompt(capability, &context, None);
+        let task_prompt = Self::build_task_prompt(
+            capability,
+            &context,
+            self.config.temp_instructions.as_deref(),
+        );
         agent
             .execute_task_streaming(capability, &task_prompt, on_chunk)
             .await

src/cli.rs

@@ -1248,9 +1248,9 @@ async fn handle_pr_with_agent(
     to: Option<String>,
     repository_url: Option<String>,
 ) -> anyhow::Result<()> {
-    use arboard::Clipboard;
     use crate::agents::{IrisAgentService, StructuredResponse, TaskContext};
     use crate::instruction_presets::PresetType;
+    use arboard::Clipboard;
 
     // Check if the preset is appropriate for PR descriptions (skip for raw output only)
     if !raw

src/studio/app/mod.rs

@@ -821,8 +821,8 @@ impl StudioApp {
 
         let handle = tokio::spawn(async move {
             let result = tokio::task::spawn_blocking(move || {
-                use crate::companion::{BranchMemory, CompanionService};
                 use super::state::CompanionSessionDisplay;
+                use crate::companion::{BranchMemory, CompanionService};
 
                 // Create companion service (this is the slow part - file watcher setup)
                 let service = CompanionService::new(repo_path, &branch)?;

src/studio/components/code_view.rs

@@ -15,6 +15,7 @@ use unicode_width::UnicodeWidthStr;
 
 use super::syntax::SyntaxHighlighter;
 use crate::studio::theme;
+use crate::studio::utils::expand_tabs;
 
 // ═══════════════════════════════════════════════════════════════════════════════
 // Code View State
@@ -269,6 +270,9 @@ fn render_code_line(
     selection: Option<(usize, usize)>,
     highlighter: Option<&SyntaxHighlighter>,
 ) -> Line<'static> {
+    // Expand tabs and strip control characters to prevent visual corruption
+    let content = expand_tabs(content, 4);
+
     let is_selected = line_num == selected_line;
     let is_in_selection =
         selection.is_some_and(|(start, end)| line_num >= start && line_num <= end);
@@ -305,7 +309,7 @@ fn render_code_line(
 
     // Add syntax-highlighted content
     if let Some(hl) = highlighter {
-        let styled_spans = hl.highlight_line(content);
+        let styled_spans = hl.highlight_line(&content);
         let mut display_width = 0;
 
         for (style, text) in styled_spans {
@@ -375,7 +379,7 @@ fn render_code_line(
             }
             format!("{}...", truncated)
         } else {
-            content.to_string()
+            content.clone()
         };
 
         spans.push(Span::styled(display_content, content_style));

src/studio/components/diff_view.rs

@@ -3,7 +3,7 @@
 //! Displays git diffs with syntax highlighting for added/removed lines.
 
 use crate::studio::theme;
-use crate::studio::utils::truncate_width;
+use crate::studio::utils::{expand_tabs, truncate_width};
 use ratatui::Frame;
 use ratatui::layout::Rect;
 use ratatui::style::{Modifier, Style};
@@ -597,15 +597,17 @@ fn render_diff_line(line: &DiffLine, line_num_width: usize, width: usize) -> Lin
 
     match line.line_type {
         DiffLineType::FileHeader => {
-            let content = format!("━━━ {} ", line.content);
+            let expanded = expand_tabs(&line.content, 4);
+            let content = format!("━━━ {} ", expanded);
             let truncated = truncate_width(&content, width);
             Line::from(vec![Span::styled(truncated, style)])
         }
         DiffLineType::HunkHeader => {
             // "     " prefix takes line_num_width * 2 + 3
+            let expanded = expand_tabs(&line.content, 4);
             let prefix_width = line_num_width * 2 + 4;
             let max_content = width.saturating_sub(prefix_width);
-            let truncated = truncate_width(&line.content, max_content);
+            let truncated = truncate_width(&expanded, max_content);
             Line::from(vec![
                 Span::styled(
                     format!("{:>width$} ", "", width = line_num_width * 2 + 3),
@@ -636,11 +638,14 @@ fn render_diff_line(line: &DiffLine, line_num_width: usize, width: usize) -> Lin
                 _ => theme::dimmed(),
             };
 
+            // Expand tabs to spaces for proper width calculation and rendering
+            let expanded_content = expand_tabs(&line.content, 4);
+
             // Calculate available width for content
             // Format: "XXXX │ XXXX +content"
             let fixed_width = line_num_width * 2 + 6; // " │ " (3) + " " (1) + prefix (1) + padding (1)
             let max_content = width.saturating_sub(fixed_width);
-            let truncated = truncate_width(&line.content, max_content);
+            let truncated = truncate_width(&expanded_content, max_content);
 
             Line::from(vec![
                 Span::styled(old_num, theme::dimmed()),

src/studio/handlers/modals/ref_selector.rs

@@ -48,10 +48,8 @@ pub fn handle(state: &mut StudioState, key: KeyEvent) -> Vec<SideEffect> {
             // Determine which ref to use:
             // 1. If there's a matching filtered ref, use that
             // 2. Otherwise, if input is not empty, use it as a custom ref (e.g., HEAD~5)
-            let ref_to_use: Option<String> = filtered
-                .get(selected)
-                .map(|s| (*s).clone())
-                .or_else(|| {
+            let ref_to_use: Option<String> =
+                filtered.get(selected).map(|s| (*s).clone()).or_else(|| {
                     if input.is_empty() {
                         None
                     } else {

src/studio/state/mod.rs

@@ -548,7 +548,10 @@ impl SettingsState {
             theme: theme_id,
             use_gitmoji: config.use_gitmoji,
             instruction_preset: config.instruction_preset.clone(),
-            custom_instructions: config.instructions.clone(),
+            custom_instructions: config
+                .temp_instructions
+                .clone()
+                .unwrap_or_else(|| config.instructions.clone()),
             available_providers,
             available_themes,
             available_presets,
@@ -977,14 +980,23 @@ impl StudioState {
     /// Create new studio state
     /// Note: Companion service is initialized asynchronously via `load_companion_async()` in app for fast startup
     pub fn new(config: Config, repo: Option<Arc<GitRepo>>) -> Self {
+        // Apply CLI overrides to commit mode
+        let mut modes = ModeStates::default();
+        if let Some(temp_instr) = &config.temp_instructions {
+            modes.commit.custom_instructions.clone_from(temp_instr);
+        }
+        if let Some(temp_preset) = &config.temp_preset {
+            modes.commit.preset.clone_from(temp_preset);
+        }
+
         Self {
             repo,
             git_status: GitStatus::default(),
             git_status_loading: false,
             config,
             active_mode: Mode::Explore,
             focused_panel: PanelId::Left,
-            modes: ModeStates::default(),
+            modes,
             modal: None,
             chat_state: ChatState::new(),
             notifications: VecDeque::new(),

src/studio/utils.rs

@@ -4,6 +4,37 @@
 
 use unicode_width::UnicodeWidthStr;
 
+// ═══════════════════════════════════════════════════════════════════════════════
+// Tab Expansion
+// ═══════════════════════════════════════════════════════════════════════════════
+
+/// Expand tab characters to spaces and strip control characters.
+///
+/// Tabs are expanded to the next multiple of `tab_width` columns.
+/// Control characters (except tab) are stripped to prevent TUI corruption.
+/// This is essential for TUI rendering where tabs and control codes
+/// would otherwise cause misalignment or visual glitches.
+pub fn expand_tabs(s: &str, tab_width: usize) -> String {
+    let mut result = String::with_capacity(s.len());
+    let mut column = 0;
+
+    for ch in s.chars() {
+        if ch == '\t' {
+            // Calculate spaces needed to reach next tab stop
+            let spaces = tab_width - (column % tab_width);
+            result.push_str(&" ".repeat(spaces));
+            column += spaces;
+        } else if !ch.is_control() {
+            // Non-control character: add to result
+            result.push(ch);
+            column += ch.to_string().width();
+        }
+        // Control characters (except tab) are silently stripped
+    }
+
+    result
+}
+
 // ═══════════════════════════════════════════════════════════════════════════════
 // String Truncation Utilities
 // ═══════════════════════════════════════════════════════════════════════════════