feat(start-work): add --worktree flag parsing from user request

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/hooks/start-work/parse-user-request.ts

@@ -0,0 +1,29 @@
+const KEYWORD_PATTERN = /\b(ultrawork|ulw)\b/gi
+const WORKTREE_FLAG_PATTERN = /--worktree(?:\s+(\S+))?/
+
+export interface ParsedUserRequest {
+  planName: string | null
+  explicitWorktreePath: string | null
+}
+
+export function parseUserRequest(promptText: string): ParsedUserRequest {
+  const match = promptText.match(/<user-request>\s*([\s\S]*?)\s*<\/user-request>/i)
+  if (!match) return { planName: null, explicitWorktreePath: null }
+
+  let rawArg = match[1].trim()
+  if (!rawArg) return { planName: null, explicitWorktreePath: null }
+
+  const worktreeMatch = rawArg.match(WORKTREE_FLAG_PATTERN)
+  const explicitWorktreePath = worktreeMatch ? (worktreeMatch[1] ?? null) : null
+
+  if (worktreeMatch) {
+    rawArg = rawArg.replace(worktreeMatch[0], "").trim()
+  }
+
+  const cleanedArg = rawArg.replace(KEYWORD_PATTERN, "").trim()
+
+  return {
+    planName: cleanedArg || null,
+    explicitWorktreePath,
+  }
+}