test: add integration tests for clone/parse/pipeline, fix chunker edge case

- tests/integration-test.ts: clones p-limit repo, parses, generates diagrams (11/11 pass)
- tests/pipeline-test.ts: mock LLM provider pipeline test (29/29 pass)
- Fix chunkCode to handle single lines exceeding maxChars limit
- Add tsx devDependency for test execution

packages/llm/src/chunker.ts

@@ -12,10 +12,21 @@ export function chunkCode(content: string, maxTokens: number): string[] {
   let currentLen = 0;
 
   for (const line of lines) {
-    if (currentLen + line.length > maxChars && current.length > 0) {
-      chunks.push(current.join("\n"));
-      current = [];
-      currentLen = 0;
+    if (currentLen + line.length > maxChars) {
+      if (current.length > 0) {
+        chunks.push(current.join("\n"));
+        current = [];
+        currentLen = 0;
+      }
+      if (line.length > maxChars) {
+        let remaining = line;
+        while (remaining.length > 0) {
+          const chunk = remaining.substring(0, maxChars);
+          chunks.push(chunk);
+          remaining = remaining.substring(maxChars);
+        }
+        continue;
+      }
     }
     current.push(line);
     currentLen += line.length + 1;