Enable keyword detection on first message using direct parts transformation

Previously, first messages were skipped entirely to avoid interfering with title generation.
Now, keywords detected on the first message are injected directly into the message parts
instead of using the hook message injection system, allowing keywords like 'ultrawork' to
activate on the first message of a session.

This change:
- Removes the early return that skipped first message keyword detection
- Moves keyword context generation before the isFirstMessage check
- For first messages: transforms message parts directly by prepending keyword context
- For subsequent messages: maintains existing hook message injection behavior

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

Author: code-yeongyu

src/hooks/keyword-detector/index.ts

@@ -25,18 +25,26 @@ export function createKeywordDetectorHook() {
       const isFirstMessage = !sessionFirstMessageProcessed.has(input.sessionID)
       sessionFirstMessageProcessed.add(input.sessionID)
 
-      if (isFirstMessage) {
-        log("Skipping keyword detection on first message for title generation", { sessionID: input.sessionID })
-        return
-      }
-
       const promptText = extractPromptText(output.parts)
       const messages = detectKeywords(promptText)
 
       if (messages.length === 0) {
         return
       }
 
+      const context = messages.join("\n")
+
+      // First message: transform parts directly (for title generation compatibility)
+      if (isFirstMessage) {
+        log(`Keywords detected on first message, transforming parts directly`, { sessionID: input.sessionID, keywordCount: messages.length })
+        const idx = output.parts.findIndex((p) => p.type === "text" && p.text)
+        if (idx >= 0) {
+          output.parts[idx].text = `${context}\n\n---\n\n${output.parts[idx].text ?? ""}`
+        }
+        return
+      }
+
+      // Subsequent messages: inject as separate message
       log(`Keywords detected: ${messages.length}`, { sessionID: input.sessionID })
 
       const message = output.message as {
@@ -46,7 +54,6 @@ export function createKeywordDetectorHook() {
         tools?: Record<string, boolean>
       }
 
-      const context = messages.join("\n")
       log(`[keyword-detector] Injecting context for ${messages.length} keywords`, { sessionID: input.sessionID, contextLength: context.length })
       const success = injectHookMessage(input.sessionID, context, {
         agent: message.agent,