refactor(hooks): rename ultrawork-mode to keyword-detector with multi-keyword support

- Detect ultrawork, search, analyze keywords (EN/KO/JP/CN/VN)
- Add session-based injection tracking (once per session)
- Remove unnecessary state management

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src/hooks/keyword-detector/detector.ts

@@ -0,0 +1,25 @@
+import {
+  KEYWORD_DETECTORS,
+  CODE_BLOCK_PATTERN,
+  INLINE_CODE_PATTERN,
+} from "./constants"
+
+export function removeCodeBlocks(text: string): string {
+  return text.replace(CODE_BLOCK_PATTERN, "").replace(INLINE_CODE_PATTERN, "")
+}
+
+export function detectKeywords(text: string): string[] {
+  const textWithoutCode = removeCodeBlocks(text)
+  return KEYWORD_DETECTORS.filter(({ pattern }) =>
+    pattern.test(textWithoutCode)
+  ).map(({ message }) => message)
+}
+
+export function extractPromptText(
+  parts: Array<{ type: string; text?: string }>
+): string {
+  return parts
+    .filter((p) => p.type === "text")
+    .map((p) => p.text || "")
+    .join(" ")
+}