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/edit-operations.ts

@@ -11,6 +11,14 @@ import {
 } from "./edit-operation-primitives"
 import { validateLineRefs } from "./validation"
 
+function arraysEqual(a: string[], b: string[]): boolean {
+  if (a.length !== b.length) return false
+  for (let i = 0; i < a.length; i++) {
+    if (a[i] !== b[i]) return false
+  }
+  return true
+}
+
 export interface HashlineApplyReport {
   content: string
   noopEdits: number
@@ -51,7 +59,7 @@ export function applyHashlineEditsWithReport(content: string, edits: HashlineEdi
         const next = edit.end
           ? applyReplaceLines(lines, edit.pos, edit.end, edit.lines, { skipValidation: true })
           : applySetLine(lines, edit.pos, edit.lines, { skipValidation: true })
-        if (next.join("\n") === lines.join("\n")) {
+        if (arraysEqual(next, lines)) {
           noopEdits += 1
           break
         }
@@ -62,7 +70,7 @@ export function applyHashlineEditsWithReport(content: string, edits: HashlineEdi
         const next = edit.pos
           ? applyInsertAfter(lines, edit.pos, edit.lines, { skipValidation: true })
           : applyAppend(lines, edit.lines)
-        if (next.join("\n") === lines.join("\n")) {
+        if (arraysEqual(next, lines)) {
           noopEdits += 1
           break
         }
@@ -73,7 +81,7 @@ export function applyHashlineEditsWithReport(content: string, edits: HashlineEdi
         const next = edit.pos
           ? applyInsertBefore(lines, edit.pos, edit.lines, { skipValidation: true })
           : applyPrepend(lines, edit.lines)
-        if (next.join("\n") === lines.join("\n")) {
+        if (arraysEqual(next, lines)) {
           noopEdits += 1
           break
         }

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
   }