feat: add runtime location override support

[olalie]

Summary

Add runtime location override support using TAPMAP_LON and TAPMAP_LAT.

This allows:

• skipping external public-IP lookup
• overriding automatic local geolocation
• setting fixed runtime coordinates without editing config.py

The PR also expands regression coverage for rolling 30-day insights persistence semantics and improves workflow naming consistency.

Changes

Runtime

• Add location_override runtime context field
• Add runtime env parsing and validation for:
  • TAPMAP_LON
  • TAPMAP_LAT
• Apply runtime override precedence before config.py resolution

UI

• Add ENV local-location mode to status line
• Add ENV semantics to About view
• Add ENV documentation to Help view

Documentation

• Document runtime location override support in README
• Document privacy behavior for public-IP lookup
• Add Docker Hub examples for runtime location override
• Document Daily Activity Report keyboard shortcut

Testing

• Add focused regression tests for runtime location override parsing
• Add validation and boundary coverage for runtime coordinate parsing
• Add comprehensive regression coverage for rolling 30-day insights bitmaps
• Add bitmap aging, pruning, and re-observation boundary tests
• Clarify and preserve internal anchor_day bitmap semantics

CI

• Clarify macOS build naming in artifact workflows

Maintenance

• Ignore full Docker runtime directory
• Fix MkDocs README list rendering
• Remove unused Flask dependency

Validation

• pytest
• 265 passed