Stop tracking credentials and internal planning documents

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -8,4 +8,26 @@ coverage/
 design-source/
 .DS_Store
 ailine
-.wrangler
+.wrangler
+
+# Credentials and signing material
+/cred.md
+/cred.txt
+*.p8
+*.p12
+*.cer
+*.pem
+*.key
+*.certSigningRequest
+*.mobileprovision
+.env
+.env.*
+!.env.example
+
+# Internal planning documents
+/AGENTS.md
+/PRODUCT.md
+/NewPRD.md
+/PRD*.md
+/task.md
+/AgentCompany-问题清单.md