Add seamless migration path from legacy agents to unified agent:
- Add AgentType field to report payloads (unified vs legacy detection)
- Update server to detect legacy agents by type instead of version
- Add UI banner showing upgrade command when legacy agents are detected
- Add deprecation notice to install-host-agent.ps1
- Create install-docker-agent.sh stub that redirects to unified installer
Legacy agents (pulse-host-agent, pulse-docker-agent) now show a "Legacy"
badge in the UI with a one-click copy command to upgrade to the unified
agent.
Implement self-update capability for the unified pulse-agent binary:
- Add internal/agentupdate package with cross-platform update logic
- Hourly version checks against /api/agent/version endpoint
- SHA256 checksum verification for downloaded binaries
- Atomic binary replacement with backup/rollback on failure
- Support for Linux, macOS, and Windows (10 platform/arch combinations)
Build and release changes:
- Dockerfile builds unified agent for all platforms
- build-release.sh includes unified agent in release artifacts
- validate-release.sh validates unified agent binaries
- Install scripts (install.sh, install.ps1) use correct URL format
Related to #727, #737
