feat(tauri): add Windows taskbar overlay badge for git sync status

This change introduces a Windows-only taskbar badge that displays the
ahead+behind count as a rendered overlay icon. The UI now updates
the badge whenever the repository sync status changes, and the git
diff commands are adjusted to avoid external diff/text conversion noise.

- Add badge rendering and Tauri command for setting overlay icon
- Wire badge updates into the Svelte app based on git status
- Update git diff invocations to disable ext-diff/textconv

.claude/settings.local.json

@@ -73,7 +73,10 @@
       "Bash(rustup target *)",
       "Bash(echo \"exit code: $?\")",
       "Read(//home/cbr/.cargo/registry/src/**)",
-      "Bash(find / -maxdepth 6 -iname \"mistralrs-*\" -type d)"
+      "Bash(find / -maxdepth 6 -iname \"mistralrs-*\" -type d)",
+      "Bash(grep -A2 '^name = \"tauri\"$' \"/mnt/c/Users/cbr/Desktop/Neuer Ordner \\(6\\)/src-tauri/Cargo.lock\")",
+      "Bash(rustfmt --edition 2024 --check src/badge.rs src/main.rs)",
+      "Bash(rustfmt --edition 2024 --check src/git.rs)"
     ]
   }
 }

src-tauri/src/badge.rs

@@ -0,0 +1,122 @@
+//! Renders the "ahead + behind" count as a small circular icon and applies it as the
+//! Windows taskbar overlay badge. Windows has no native numeric taskbar badge (unlike
+//! macOS/Linux, which support `Window::set_badge_count`), so the number has to be drawn
+//! into a plain RGBA icon ourselves and set via `Window::set_overlay_icon`.
+
+use tauri::Manager;
+use tauri::image::Image;
+
+const GLYPH_WIDTH: usize = 3;
+const GLYPH_HEIGHT: usize = 5;
+
+/// A minimal 3x5 pixel-grid font, just enough to draw digits and "+" legibly at badge size.
+fn glyph_rows(ch: char) -> [&'static str; GLYPH_HEIGHT] {
+    match ch {
+        '0' => ["111", "101", "101", "101", "111"],
+        '1' => ["010", "110", "010", "010", "111"],
+        '2' => ["111", "001", "111", "100", "111"],
+        '3' => ["111", "001", "111", "001", "111"],
+        '4' => ["101", "101", "111", "001", "001"],
+        '5' => ["111", "100", "111", "001", "111"],
+        '6' => ["111", "100", "111", "101", "111"],
+        '7' => ["111", "001", "010", "010", "010"],
+        '8' => ["111", "101", "111", "101", "111"],
+        '9' => ["111", "101", "111", "001", "111"],
+        '+' => ["000", "010", "111", "010", "000"],
+        _ => ["000", "000", "000", "000", "000"],
+    }
+}
+
+/// Renders `text` (digits / "+" only) centered on a filled circle, at `size`x`size` pixels,
+/// scaling each font pixel up by `scale` so it stays legible once Windows shrinks it down
+/// for the taskbar.
+fn render_circle_with_text(text: &str, size: usize, scale: usize) -> Vec<u8> {
+    let mut rgba = vec![0u8; size * size * 4];
+
+    // Filled circle background with a slightly darker rim for contrast against any
+    // taskbar/background color.
+    let center = size as f32 / 2.0;
+    let radius = size as f32 / 2.0 - 1.0;
+    const FILL_COLOR: [u8; 4] = [220, 53, 69, 255];
+    const BORDER_COLOR: [u8; 4] = [176, 32, 48, 255];
+    for y in 0..size {
+        for x in 0..size {
+            let dx = x as f32 + 0.5 - center;
+            let dy = y as f32 + 0.5 - center;
+            let dist = (dx * dx + dy * dy).sqrt();
+            if dist <= radius {
+                let color = if dist >= radius - 2.0 { BORDER_COLOR } else { FILL_COLOR };
+                let idx = (y * size + x) * 4;
+                rgba[idx..idx + 4].copy_from_slice(&color);
+            }
+        }
+    }
+
+    let glyphs: Vec<[&'static str; GLYPH_HEIGHT]> = text.chars().map(glyph_rows).collect();
+    let glyph_px_w = GLYPH_WIDTH * scale;
+    let glyph_px_h = GLYPH_HEIGHT * scale;
+    let gap = scale;
+    let total_w = glyphs.len() * glyph_px_w + gap * glyphs.len().saturating_sub(1);
+    let start_x = size.saturating_sub(total_w) / 2;
+    let start_y = size.saturating_sub(glyph_px_h) / 2;
+
+    for (gi, rows) in glyphs.iter().enumerate() {
+        let glyph_x = start_x + gi * (glyph_px_w + gap);
+        for (gy, row) in rows.iter().enumerate() {
+            for (gx, pixel) in row.chars().enumerate() {
+                if pixel != '1' {
+                    continue;
+                }
+                for py in 0..scale {
+                    for px in 0..scale {
+                        let x = glyph_x + gx * scale + px;
+                        let y = start_y + gy * scale + py;
+                        if x < size && y < size {
+                            let idx = (y * size + x) * 4;
+                            rgba[idx..idx + 4].copy_from_slice(&[255, 255, 255, 255]);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    rgba
+}
+
+/// Renders the badge icon for a given count. Caps the displayed text at "9+" since the
+/// badge is only large enough for two characters to stay legible.
+fn render_badge_icon(count: u32) -> Image<'static> {
+    const SIZE: usize = 40;
+    const SCALE: usize = 4;
+    let text = if count > 9 { "9+".to_string() } else { count.to_string() };
+    let rgba = render_circle_with_text(&text, SIZE, SCALE);
+    Image::new_owned(rgba, SIZE as u32, SIZE as u32)
+}
+
+/// Sets the taskbar badge to `ahead + behind` (0 clears it). Windows-only: Windows has no
+/// native numeric badge API, so this draws and applies a small overlay icon instead. No-op
+/// on other platforms — non-Windows desktops should use `Window::set_badge_count` for a
+/// real native badge instead, which this app doesn't currently wire up.
+#[tauri::command]
+pub fn set_sync_badge(app: tauri::AppHandle, ahead: u32, behind: u32) -> Result<(), String> {
+    let total = ahead + behind;
+
+    #[cfg(target_os = "windows")]
+    {
+        let Some(window) = app.get_webview_window("main") else {
+            return Ok(());
+        };
+        let icon = if total == 0 { None } else { Some(render_badge_icon(total)) };
+        window
+            .set_overlay_icon(icon)
+            .map_err(|err| format!("Could not set taskbar badge: {err}"))?;
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    {
+        let _ = (app, total);
+    }
+
+    Ok(())
+}

src-tauri/src/git.rs

@@ -1302,6 +1302,8 @@ pub fn compare_commits(
         &repo,
         [
             "diff",
+            "--no-ext-diff",
+            "--no-textconv",
             "-M",
             FULL_FILE_DIFF_CONTEXT,
             from_hash.as_str(),
@@ -1344,7 +1346,14 @@ pub fn diff_file_against_working_tree(
     )?;
     let patch_output = run_git_with_paths(
         &repo,
-        &["diff", "-M", FULL_FILE_DIFF_CONTEXT, commit_hash.as_str()],
+        &[
+            "diff",
+            "--no-ext-diff",
+            "--no-textconv",
+            "-M",
+            FULL_FILE_DIFF_CONTEXT,
+            commit_hash.as_str(),
+        ],
         std::slice::from_ref(&file),
     )?;
 
@@ -1400,6 +1409,8 @@ pub fn compare_file_to_head(
         &repo,
         &[
             "diff",
+            "--no-ext-diff",
+            "--no-textconv",
             "-M",
             FULL_FILE_DIFF_CONTEXT,
             commit_hash.as_str(),
@@ -1472,6 +1483,8 @@ pub fn compare_file_to_parent(
         &repo,
         &[
             "diff",
+            "--no-ext-diff",
+            "--no-textconv",
             "-M",
             FULL_FILE_DIFF_CONTEXT,
             from_hash.as_str(),

src-tauri/src/main.rs

@@ -1,7 +1,9 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
+mod badge;
 mod git;
 
+use badge::set_sync_badge;
 use git::{
     SearchCancellationState, apply_file_patch, cancel_code_search, cancel_file_history,
     checkout_branch, commit, commit_ai_generate, commit_ai_load, commit_ai_local_models,
@@ -62,7 +64,8 @@ fn main() {
             get_remote_url,
             cred_load,
             cred_save,
-            cred_delete
+            cred_delete,
+            set_sync_badge
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");

src/App.svelte

@@ -63,6 +63,7 @@
     restoreFiles,
     restoreToCommit,
     searchCodeIntroductions,
+    setSyncBadge,
     stageFiles,
     unstageFiles,
   } from "./lib/git";
@@ -656,6 +657,7 @@
       repoPath = "";
       status = null;
       lastStatusFingerprint = "";
+      void setSyncBadge(0, 0).catch(() => {});
     }
     branches = [];
     commits = [];
@@ -689,6 +691,7 @@
     repoPath = activeRepoPath;
     lastStatusFingerprint = statusFingerprint(nextStatus);
     upsertRepoTab(activeRepoPath, nextStatus);
+    void setSyncBadge(nextStatus.ahead, nextStatus.behind).catch(() => {});
   }
 
   function errorToMessage(error: unknown): string {

src/lib/git.ts

@@ -37,6 +37,12 @@ export function getStatus(path: string): Promise<GitStatus> {
   return invoke<GitStatus>("get_status", { path });
 }
 
+// Sets the taskbar icon badge to ahead + behind (0 clears it). Windows only — a no-op on
+// other platforms, since Windows has no native numeric badge to fall back to.
+export function setSyncBadge(ahead: number, behind: number): Promise<void> {
+  return invoke<void>("set_sync_badge", { ahead, behind });
+}
+
 export function listBranches(path: string): Promise<GitBranch[]> {
   return invoke<GitBranch[]>("list_branches", { path });
 }