fix(hook-message-injector): add validation to prevent empty message injection and improve logging

- Add content validation in injectHookMessage() to prevent empty hook content injection
- Add logging to claude-code-hooks and keyword-detector for better debugging
- Document timing issues in empty-message-sanitizer comments
- Update README with improved setup instructions

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/claude-code-hooks/index.ts

@@ -111,6 +111,7 @@ export function createClaudeCodeHooksHook(ctx: PluginInput, config: PluginConfig
 
         if (result.messages.length > 0) {
           const hookContent = result.messages.join("\n\n")
+          log(`[claude-code-hooks] Injecting ${result.messages.length} hook messages`, { sessionID: input.sessionID, contentLength: hookContent.length })
           const message = output.message as {
             agent?: string
             model?: { modelID?: string; providerID?: string }