feat(packaging): add Debian packaging and APT repository scripts

debian/DEBIAN/control: package metadata, depends on python3.11+, postgresql-client
debian/DEBIAN/postinst: creates activeblue-ai system user, installs venv, enables service
debian/DEBIAN/prerm: stops and disables service before removal
debian/DEBIAN/postrm: purge removes config, logs, venv, and system user
debian/lib/systemd/system/activeblue-ai.service:
  - Runs as dedicated user with PrivateTmp + ProtectSystem hardening
  - EnvironmentFile=/etc/activeblue-ai/.env
  - Restart=on-failure with 5s backoff
debian/usr/bin/activeblue-ai: CLI with start/stop/restart/status/logs/migrate/health/sweep/privacy/version
build_deb.sh: builds activeblue-ai_X.Y.Z_all.deb in dist/
publish_repo.sh: scans packages, generates Release + checksums, optional GPG signing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

debian/DEBIAN/control

@@ -0,0 +1,15 @@
+Package: activeblue-ai
+Version: 0.1.0
+Section: misc
+Priority: optional
+Architecture: all
+Depends: python3 (>= 3.11), python3-pip, python3-venv, postgresql-client
+Maintainer: ActiveBlue <admin@activeblue.net>
+Homepage: https://activeblue.net
+Description: ActiveBlue AI Agent Service
+ Multi-agent AI system integrated with Odoo 18 Community.
+ Provides a FastAPI service with 8 specialist AI agents for finance,
+ accounting, CRM, sales, project management, eLearning, expenses, and HR.
+ .
+ Supports local (Ollama), hybrid, and cloud (Claude) LLM backends.
+ HIPAA-sensitive agents are enforced to use local LLM only.