perf: pre-compile regex patterns and optimize hot-path string operations

- error-classifier: pre-compile default retry pattern regex
- think-mode/detector: combine multilingual patterns into single regex
- parser: skip redundant toLowerCase on pre-lowered keywords
- edit-operations: use fast arraysEqual instead of JSON comparison
- hash-computation: optimize streaming line extraction with index tracking

src/tools/hashline-edit/hash-computation.ts

@@ -86,15 +86,17 @@ export async function* streamHashLinesFromUtf8(
     pending += text
     const chunksToYield: string[] = []
 
+    let lastIdx = 0
     while (true) {
-      const idx = pending.indexOf("\n")
+      const idx = pending.indexOf("\n", lastIdx)
       if (idx === -1) break
-      const line = pending.slice(0, idx)
-      pending = pending.slice(idx + 1)
+      const line = pending.slice(lastIdx, idx)
+      lastIdx = idx + 1
       endedWithNewline = true
       chunksToYield.push(...pushLine(line))
     }
 
+    pending = pending.slice(lastIdx)
     if (pending.length > 0) endedWithNewline = false
     return chunksToYield
   }