Support DuckDB spatial and shapefile uploads

[philippjfr]

Adds support for loading DuckDB spatial columns and allows uploading shapefiles.

• Check that uploaded zipfile actually contains shapefile data
• Support other geometry file types

[codecov]

Codecov Report

Attention: Patch coverage is 9.52381% with 38 lines in your changes missing coverage. Please review.

Project coverage is 55.81%. Comparing base (b777a29) to head (5bae144).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
lumen/ai/controls.py	0.00%	30 Missing ⚠️
lumen/sources/duckdb.py	50.00%	4 Missing ⚠️
lumen/ai/agents.py	0.00%	2 Missing ⚠️
lumen/ai/assistant.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #715      +/-   ##
==========================================
- Coverage   55.94%   55.81%   -0.14%     
==========================================
  Files          98       98              
  Lines       11845    11879      +34     
==========================================
+ Hits         6627     6630       +3     
- Misses       5218     5249      +31     

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