bump version to v0.2.9

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

Stacker v0.2.8

chore: bump version to v0.2.7

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

release: v0.2.6

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Add release build instructions and docker release tags

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix: replace softprops action with gh release upload to avoid finaliz…

…e retry bug

Update diagram in README for Stacker architecture

align diagram

fix: container discovery now uses list_containers results instead of …

…health checks

The discover endpoint was only seeing containers that appeared in health check
results. But health checks only return registered apps + system patterns.
Now it:
1. First looks for list_containers command results (has ALL containers)
2. Falls back to health check results if no list_containers found
3. Properly parses system_containers array from health results

This allows discovering unregistered containers like nginx-proxy-manager.

fix docker.yml copy dist, npm fix