Multi-core simulation: grain movement and heat across a worker pool (t88 phase 3)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

build.py

@@ -35,9 +35,13 @@ def main():
     shell = (src / man['shell']).read_text()
     css, _ = join(man['css'])
     js, starts = join(man['sim'] + man['client'])
+    sim, _ = join(man['sim'])
+    # Keep worker code outside the indexed script so source line mappings stay exact.
+    worker = '<script>const SIM_WORKER_SOURCE=' + json.dumps(sim).replace('</', '<\\/') + ';</script>'
     head, tail = shell.split('//__JS__')
     body = head.replace('/*__CSS__*/', css)
     page = body + js + tail
+    page = worker + page
     pre = ('<!doctype html><html><head><meta charset="utf-8">'
            '<meta name="viewport" content="width=device-width,initial-scale=1,viewport-fit=cover">'
            '</head><body>')
@@ -46,7 +50,7 @@ def main():
     (dist / 'deepgrain-foundry.html').write_text(page)
     (dist / 'index.html').write_text(full)
     # the script starts on this line of index.html (the doctype prefix has no newlines)
-    js_line = body.count('\n') + 1
+    js_line = worker.count('\n') + body.count('\n') + 1
     (dist / 'bundle-lines.json').write_text(json.dumps(
         {'page': 'dist/index.html', 'files': [[js_line + s - 1, f] for s, f in starts]}, indent=1) + '\n')
     print(f'built dist/index.html ({len(full):,} bytes, {len(starts)} source files)')