feat: expand Files features; add file associations

programs/src/desktop/main.cpp

@@ -181,6 +181,27 @@ void desktop_scan_apps(DesktopState* ds) {
             snprintf(item->binary_path, sizeof(item->binary_path),
                      "0:/apps/%s/%s", dirname, binary);
 
+            // File types the app opens, used by Files for default apps and
+            // "Open With". Stored lowercased as " ext1 ext2 " for whole-word
+            // matching; entries that would overflow the buffer are dropped.
+            if (auto* types = doc.get_array("files.types")) {
+                int len = 0;
+                item->file_types[len++] = ' ';
+                for (int t = 0; t < types->array.count; t++) {
+                    auto* v = types->array.items[t];
+                    if (v->type != montauk::toml::Type::String || !v->str[0]) continue;
+                    const char* ext = v->str[0] == '.' ? v->str + 1 : v->str;
+                    int elen = montauk::slen(ext);
+                    if (elen == 0 || len + elen + 2 > (int)sizeof(item->file_types)) continue;
+                    for (int k = 0; k < elen; k++) {
+                        char ch = ext[k];
+                        item->file_types[len++] = (ch >= 'A' && ch <= 'Z') ? ch + 32 : ch;
+                    }
+                    item->file_types[len++] = ' ';
+                }
+                item->file_types[len < 2 ? 0 : len] = '\0';
+            }
+
             // Load icon from app directory
             item->icon = {};
             item->icon_path[0] = '\0';