Fix smart match empty output: replace async spawn with spawnSync

The async spawn() had a race condition where the 'close' event fired
before all stdout/stderr data was collected, resulting in "(empty)"
output. Replaced with spawnSync() which guarantees all output is
captured before returning. Also logs the exact command being run.

Bumped to v0.9.28 for fresh AppImage filename.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: nodeeeeee

electron/main.js

@@ -1034,49 +1034,43 @@ function registerIpc() {
       }
     }
 
-    // Run the actual matching script
-    const cmd = [python, script, '--course', String(cid),
-                 '--suggest-matches', '--match-model', model || 'bge-m3'];
+    // Run the actual matching script (synchronous — takes a few seconds)
+    const args = [script, '--course', String(cid),
+                  '--suggest-matches', '--match-model', model || 'bge-m3'];
+    diagLines.push(`Command: ${python} ${args.join(' ')}`);
+    const diagStr2 = diagLines.join('\n');
 
-    return new Promise((resolve) => {
-      let proc;
-      try {
-        proc = spawn(cmd[0], cmd.slice(1), {
-          env: { ...process.env, AUTONOTE_DATA_DIR: DATA_DIR },
-          stdio: ['ignore', 'pipe', 'pipe'],
-        });
-      } catch (e) {
-        resolve({ __error: `Failed to spawn process: ${e.message}\n\n${diagStr}` });
-        return;
-      }
-      let stdout = '';
-      let stderr = '';
-      proc.stdout.on('data', d => { stdout += d.toString(); });
-      proc.stderr.on('data', d => { stderr += d.toString(); });
-      proc.on('error', (e) => {
-        resolve({ __error: `Process error: ${e.message}\n\n${diagStr}` });
-      });
-      proc.on('close', (code) => {
-        const combined = stdout + '\n' + stderr;
-        if (code !== 0) {
-          resolve({ __error: `Exit code ${code}:\n${combined.trim()}\n\n── Diagnostics ──\n${diagStr}` });
-          return;
-        }
-        const marker = '__MATCH_RESULT__';
-        const idx = combined.indexOf(marker);
-        if (idx < 0) {
-          resolve({ __error: `No results marker in output:\n${combined.trim()}\n\n── Diagnostics ──\n${diagStr}` });
-          return;
-        }
-        try {
-          const result = JSON.parse(combined.slice(idx + marker.length).trim());
-          result.__log = combined.slice(0, idx).trim();
-          resolve(result);
-        } catch (e) {
-          resolve({ __error: `JSON parse error: ${e.message}\n${combined.trim()}` });
-        }
+    let result;
+    try {
+      result = spawnSync(python, args, {
+        encoding: 'utf8',
+        timeout: 120000,  // 2 minutes max
+        env: { ...process.env, AUTONOTE_DATA_DIR: DATA_DIR },
+        stdio: ['ignore', 'pipe', 'pipe'],
       });
-    });
+    } catch (e) {
+      return { __error: `Failed to run: ${e.message}\n\n── Diagnostics ──\n${diagStr2}` };
+    }
+
+    const combined = (result.stdout || '') + '\n' + (result.stderr || '');
+
+    if (result.status !== 0) {
+      return { __error: `Exit code ${result.status}:\n${combined.trim()}\n\n── Diagnostics ──\n${diagStr2}` };
+    }
+
+    const marker = '__MATCH_RESULT__';
+    const idx = combined.indexOf(marker);
+    if (idx < 0) {
+      return { __error: `No results in output:\n${combined.trim()}\n\n── Diagnostics ──\n${diagStr2}` };
+    }
+
+    try {
+      const parsed = JSON.parse(combined.slice(idx + marker.length).trim());
+      parsed.__log = combined.slice(0, idx).trim();
+      return parsed;
+    } catch (e) {
+      return { __error: `JSON parse error: ${e.message}\n${combined.trim()}` };
+    }
   });
 
   ipcMain.handle('align:saveMapping', (_, { cid, mapping }) => {

electron/package.json

@@ -1,6 +1,6 @@
 {
   "name": "auto-note",
-  "version": "0.9.27",
+  "version": "0.9.28",
   "description": "AutoNote — lecture notes generator from Canvas recordings",
   "homepage": "https://github.com/nodeeeeee/Auto-Note",
   "author": {