docs: regenerate API reference for container metadata hooks; bump version to 0.6.0

[tombonfert]

Summary

Documentation and release housekeeping. No source code or behavior changes.

• Bump VERSION from 0.5.2 to 0.6.0.
• Regenerate API reference docs to match the current docstrings:
  • Add attach_container_metadata to query_solver (no-op base hook) and
    default_solver (left-joins requested container tags/metrics onto the
    channel-match frame, with optional pre_filtered_containers_df scoping).
  • Tighten the TimeSeriesSelector docs for the series_type and
    value_type (POINTS_IN_TIME) parameters.

Testing

Docs-only change; no tests affected.

Test Plan

• Unit tests added/updated
• Manual testing completed
• Documentation updated (if applicable)

Checklist

• Code follows project style guidelines
• Self-review completed
• No new linter warnings introduced

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.37%. Comparing base (dfbf0a1) to head (0470fe9).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #89   +/-   ##
=======================================
  Coverage   89.37%   89.37%           
=======================================
  Files          62       62           
  Lines        5544     5544           
  Branches      680      680           
=======================================
  Hits         4955     4955           
  Misses        466      466           
  Partials      123      123           

Flag	Coverage Δ
query_engine	85.83% <ø> (ø)
reporting	94.25% <ø> (ø)

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