dev: oh my Claude

Sometimes tool use requests are streamed as JSON, but sometimes they're
streamed as an empty string (causing the JSON parser to error). Had they
not streamed anything we actually would've responded correctly, but
what they stream implies "this empty string is the JSON input" which is
incorrect. Oh well.

src/backend/src/modules/puterai/ClaudeService.js

@@ -209,6 +209,13 @@ class ClaudeService extends BaseService {
                                 on_event: (event) => {
                                     if ( event.type === 'content_block_stop' ) {
                                         state = STATES.ready;
+                                        
+                                        // Yeah... claude will send an empty string instead of
+                                        // an empty object when there's no input. So we have to
+                                        // check for that. Good job, Anthropic.
+                                        if ( buffer === '' ) {
+                                            buffer = '{}';
+                                        }
                                         const str = JSON.stringify({
                                             tool_use: {
                                                 ...content_block,