Linux: native file icons via freedesktop-icons

- Replace file_icon_provider (GTK, main-thread-only) with
  freedesktop-icons + mime_guess on Linux (pure Rust, thread-safe)
- ext → MIME type → XDG icon name → theme lookup (Adwaita, Yaru, etc.)
- file_icon_provider moved to macOS-only dependency
- SVGs skipped (no renderer); falls back through generic icon names

Author: vdavid

AGENTS.md

@@ -155,6 +155,7 @@ There are two MCP servers available to you:
 - When getting oriented, consider the docs: `docs` folder and `CLAUDE.md` files in each directory.
 - When coming up with a plan for a development, save it to `docs/specs/{feature}-plan.md` in this repo (we clean out old
   plans every few weeks/months, git history remembers them).
+- Don't enter "Plan mode" unless specifically asked to.
 - When writing a plan, always capture the INTENTION behind the plan, not just the steps. That way, the implementing
   agent or human will know the "why"s behind the decisions and can adapt dynamically if it makes an unexpected discovery
   during implementation.

Cargo.lock

@@ -39,7 +39,6 @@ serde_json = "1"
 notify = "8"
 dirs = "6"
 uzers = "0.12.2"
-file_icon_provider = "0.4.0"
 image = "0.25.9"
 base64 = "0.22.1"
 rayon = "1.11.0"
@@ -91,6 +90,10 @@ keyring = "3"
 cocoon = "0.4"
 # D-Bus client for XDG Desktop Portal (accent color, appearance settings)
 zbus = "5"
+# Native file icons: XDG icon theme lookup (pure Rust, no GTK dependency)
+freedesktop-icons = "0.4"
+# MIME type guessing from file extensions (for icon name resolution)
+mime_guess = "2"
 
 [target.'cfg(any(target_os = "macos", target_os = "linux"))'.dependencies]
 # MTP (Android device) support via pure Rust implementation
@@ -105,6 +108,7 @@ smb = "0.11.1"
 smb-rpc = "=0.11.1"
 
 [target.'cfg(target_os = "macos")'.dependencies]
+file_icon_provider = "0.4.0"
 core-foundation = "0.10.1"
 core-services = "1.0.0"
 icns = "0.3.1"

apps/desktop/src-tauri/Cargo.toml

@@ -6,14 +6,18 @@
 
 use crate::config::ICON_SIZE;
 use base64::Engine;
-use file_icon_provider::get_file_icon;
 use image::{DynamicImage, ImageFormat, imageops::FilterType};
 use rayon::prelude::*;
 use std::collections::HashMap;
 use std::io::Cursor;
 use std::path::{Path, PathBuf};
 use std::sync::RwLock;
 
+// file_icon_provider uses GTK on Linux which requires main-thread access and
+// fails silently from rayon/tokio threads. On Linux we use freedesktop-icons instead.
+#[cfg(target_os = "macos")]
+use file_icon_provider::get_file_icon;
+
 /// Cache for generated icons (icon_id -> base64 WebP data URL)
 static ICON_CACHE: RwLock<Option<HashMap<String, String>>> = RwLock::new(None);
 
@@ -82,7 +86,8 @@ fn image_to_data_url(img: &DynamicImage) -> Option<String> {
     Some(format!("data:image/webp;base64,{}", base64))
 }
 
-/// Fetches icon for a specific file path.
+/// Fetches icon for a specific file path via the OS icon provider (macOS).
+#[cfg(target_os = "macos")]
 fn fetch_icon_for_path(path: &Path) -> Option<String> {
     // Get icon from OS (size is u16)
     let icon = get_file_icon(path, ICON_SIZE as u16).ok()?;
@@ -94,6 +99,19 @@ fn fetch_icon_for_path(path: &Path) -> Option<String> {
     image_to_data_url(&dynamic_img)
 }
 
+/// Fetches icon for a specific file path via XDG icon theme lookup.
+#[cfg(target_os = "linux")]
+fn fetch_icon_for_path(path: &Path) -> Option<String> {
+    let icon_id = if path.is_dir() {
+        "dir".to_string()
+    } else if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
+        format!("ext:{}", ext.to_lowercase())
+    } else {
+        "file".to_string()
+    };
+    crate::linux_icons::get_icon_for_id(&icon_id, ICON_SIZE as u16).and_then(|img| image_to_data_url(&img))
+}
+
 /// Gets icon for a path as base64 data URL.
 /// Public API for use by volumes module.
 pub fn get_icon_for_path(path: &str) -> Option<String> {
@@ -157,7 +175,17 @@ pub fn get_icons(icon_ids: Vec<String>, use_app_icons_for_documents: bool) -> Ha
         #[cfg(not(target_os = "macos"))]
         let _ = use_app_icons_for_documents;
 
-        // Default path: use sample file approach
+        // Linux: look up directly from XDG icon theme (no temp files needed)
+        #[cfg(target_os = "linux")]
+        if let Some(img) = crate::linux_icons::get_icon_for_id(&icon_id, ICON_SIZE as u16)
+            && let Some(data_url) = image_to_data_url(&img)
+        {
+            cache_icon(icon_id.clone(), data_url.clone());
+            result.insert(icon_id, data_url);
+            continue;
+        }
+
+        // macOS/Windows: use sample file approach (Launch Services / Shell)
         if let Some(sample_path) = get_sample_path_for_icon_id(&icon_id)
             && let Some(data_url) = fetch_icon_for_path(&sample_path)
         {

apps/desktop/src-tauri/src/icons.rs

@@ -81,6 +81,8 @@ mod indexing;
 pub mod licensing;
 #[cfg(target_os = "linux")]
 pub(crate) mod linux_distro;
+#[cfg(target_os = "linux")]
+mod linux_icons;
 #[cfg(target_os = "macos")]
 mod macos_icons;
 mod mcp;