fix: harden CMS security - password hashing, XSS, session persistence, sensitive data exposure

docs: update progress notes for Features #21, #23

feat: implement Features #21, #23 - AI CLI commands for providers and embeddings

feat: verify Feature #20 - Fallback provider chains work

feat: implement Features #12, #13 - AI image classification and content moderation

docs: update progress notes for Features #9, #10, #11

feat: implement Features #9, #10, #11 - AI operations (TTS, STT, TTI)

feat: implement Features #6, #8, #18 - AI operations with usage tracking

Fix regression in Feature 6: Chat operation with streaming support

docs: verify Feature #14 - AI provider configuration UI works correctly

feat: implement Features #6, #7, #22 - AI chat operations and CLI

feat: implement Feature #19 - AI provider rate limiting

Fix regression in Ollama provider implementation

docs: session complete - Features #17 and #24 verified and passing

feat: implement Feature #24 - CLI ai:test command for provider connectivity testing