Fix segfault: keep JSON body alive for parsed string refs

- Root cause: parseFromSlice returns slices pointing into the raw JSON
  body, but body was freed immediately after parsing in getUpdates
- Fix: return OwnedParsed wrapper that keeps both parsed result and
  raw body alive together
- Switch HTTP layer to curl subprocess (more reliable than std.http
  with static linking)
- Fix downloadToFile: use spawnAndWait instead of collectOutput
  (collectOutput requires both pipes)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main.zig

@@ -24,14 +24,14 @@ pub fn main() !void {
     var offset: i64 = 0;
 
     while (true) {
-        const updates = bot.getUpdates(offset, 30) catch |err| {
+        var updates = bot.getUpdates(offset, 30) catch |err| {
             log.err("getUpdates failed: {s}", .{@errorName(err)});
             std.Thread.sleep(5 * std.time.ns_per_s);
             continue;
         };
         defer updates.deinit();
 
-        for (updates.value.result) |update| {
+        for (updates.parsed.value.result) |update| {
             offset = update.update_id + 1;
             processUpdate(allocator, &bot, update, whisper_url, language);
         }
@@ -80,15 +80,19 @@ fn handleTranscription(
     language: []const u8,
 ) !void {
     // Get file path from Telegram
+    log.info("Step 1: getFilePath", .{});
     const file_path = try bot.getFilePath(file_id);
     defer allocator.free(file_path);
+    log.info("Step 1 done: {s}", .{file_path});
 
     // Download file
     const ext: []const u8 = if (is_video) ".mp4" else ".ogg";
     const tmp_input = try std.fmt.allocPrint(allocator, "/tmp/tg_{d}{s}", .{ message.message_id, ext });
     defer allocator.free(tmp_input);
 
+    log.info("Step 2: downloadFile to {s}", .{tmp_input});
     try bot.downloadFile(file_path, tmp_input);
+    log.info("Step 2 done", .{});
     defer std.fs.deleteFileAbsolute(tmp_input) catch {};
 
     // Convert video to audio if needed
@@ -100,6 +104,7 @@ fn handleTranscription(
     };
 
     if (is_video) {
+        log.info("Step 2.5: ffmpeg conversion", .{});
         const out_path = try std.fmt.allocPrint(allocator, "/tmp/tg_{d}.ogg", .{message.message_id});
         tmp_audio = out_path;
 
@@ -117,15 +122,21 @@ fn handleTranscription(
         }
 
         audio_path = out_path;
+        log.info("Step 2.5 done", .{});
     }
 
     // Transcribe
+    log.info("Step 3: transcribe {s}", .{audio_path});
     const text = try whisper.transcribe(allocator, whisper_url, audio_path, language);
     defer allocator.free(text);
+    log.info("Step 3 done, text length: {d}", .{text.len});
 
+    // Send response
+    log.info("Step 4: sendMessage", .{});
     if (text.len == 0) {
         try bot.sendMessage(message.chat.id, "(empty transcription)", message.message_id);
     } else {
         try bot.sendMessage(message.chat.id, text, message.message_id);
     }
+    log.info("Step 4 done", .{});
 }