WFS keywords

[esgn]

closes #41

Summary

• Add WFS collection keyword extraction from GetCapabilities
• Filter generic/noisy WFS keywords from application collections
• Add wfs-keywords CLI command to inspect public GPF WFS keyword occurrences
• Index collection keywords in MiniSearch
• Preserve WFS-provided keywords through merge while keeping overwrites from overriding them
• Normalize README line endings to LF and document the new CLI command

Details

• WfsClient now reads keywords through getFeatureTypeSummary() while keeping getFeatureTypes() as the collection listing source.
• Generic keywords such as feature, features, WFS, demo, test, and similar noisy values are filtered from stored collections.
• The CLI command wfs-keywords queries the public GPF WFS directly and prints keyword occurrence counts, with an optional --filtered mode.
• MiniSearch now indexes the optional keywords field and supports fields: ['keywords'].
• CollectionOverwrite no longer accepts keywords, making the merge contract explicit: keywords come from the WFS source, not overwrite files.

Validation

• npm run typecheck
• npm test
• git diff --check

[mborne]

comment function to explain that it normalize keywords (lowercase without diacritics), filter duplicates and remove generic ones.