fix(library): create the default library folder on first run (#79)

The Python server only seeds bundled starter content (and scans) when
DLC_DIR.is_dir() is true, and it can't bootstrap the folder itself — the
seed's mkdir runs only after _get_dlc_dir() already resolves a directory. On a
fresh install the default library path didn't exist, so the scan bailed with
"DLC folder not configured" and starter content never seeded.

Create the resolved DLC dir in startPython() before spawning the server so the
first scan seeds the bundled songs. Also modernize the default library path to
~/.local/share/feedback/library, keeping the legacy slopsmith paths as
fallbacks so existing installs that relied on the default keep their populated
library.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/main/python.ts

@@ -435,17 +435,24 @@ function getDLCDir(): string {
         } catch { /* ignore */ }
     }
 
-    // Common default locations
-    const home = process.env.HOME || process.env.USERPROFILE || '';
+    // Default library location. `feedback` is the current brand; the legacy
+    // `slopsmith` paths stay as fallbacks so existing installs that relied on
+    // the default keep pointing at their already-populated library.
+    // Resolve home via Electron (USERPROFILE on Windows, $HOME on Unix) rather
+    // than raw env — an empty/ MSYS-style env would otherwise make the mkdir
+    // below create the library relative to cwd or under the wrong home.
+    const home = app.getPath('home');
+    const preferred = path.join(home, '.local', 'share', 'feedback', 'library');
     const candidates = [
-        path.join(home, '.local', 'share', 'slopsmith', 'library'),
-        path.join(home, 'Music', 'Slopsmith'),
+        preferred,
+        path.join(home, '.local', 'share', 'slopsmith', 'library'), // legacy
+        path.join(home, 'Music', 'Slopsmith'),                      // legacy
     ];
     for (const dir of candidates) {
         if (fs.existsSync(dir)) return dir;
     }
 
-    return candidates[0]; // fallback even if not found
+    return preferred; // fresh install — nothing exists yet
 }
 
 export async function startPython(): Promise<void> {
@@ -490,6 +497,17 @@ export async function startPython(): Promise<void> {
     serverPort = await findPort(PREFERRED_PORT);
     const configDir = getConfigDir();
     const dlcDir = getDLCDir();
+    // Ensure the resolved library folder exists before the server starts. The
+    // Python side only seeds starter content (and scans) when DLC_DIR.is_dir()
+    // is true, and it can't bootstrap the folder itself (the seed's mkdir runs
+    // only after the dir already resolves). Creating it here makes a fresh
+    // install seed the bundled starter songs on its first scan instead of
+    // reporting "DLC folder not configured".
+    try {
+        fs.mkdirSync(dlcDir, { recursive: true });
+    } catch (err) {
+        console.warn(`[python] could not create DLC dir ${dlcDir}:`, err);
+    }
     const pluginsDir = getPluginsDir();
     const slopsmithPlugins = path.join(slopsmithDir, 'plugins');