[DOCS] Add blog post: raster analysis in SedonaDB 0.4.1

[jiayuasu]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Development Guide

Is this PR related to a ticket?

• No:
  • this is a documentation update. The PR name follows the format [DOCS] my subject

What changes were proposed in this PR?

New blog post, "SELECT * FROM Satellite", a tutorial on the raster layer that shipped in SedonaDB 0.4.1, worked end to end on the Gironde/Landes wildfire of July 2026 using Planet's open Crisis Response imagery.

• Reads the event's STAC-GeoParquet index over HTTPS and selects scenes with ST_Intersects
• Opens the PlanetScope surface-reflectance COGs as out-db rasters with RS_FromPath, clips them with RS_Clip, and aligns them onto a 12 m reference grid built with Raster.from_numpy and passed as a query parameter to RS_ReprojectMatch; the scenes of a date are read in one statement
• NDVI drop with an Otsu threshold in NumPy, back into SQL as a raster parameter
• RS_Polygonize turns the burn mask into 173 polygons (24,091 ha), RS_ZonalStats sums it per Overture commune, ESA WorldCover aligned to the same grid gives the land-cover breakdown, RS_AsGeoTiff writes the mask out
• Figures: cover and burn-scar map from the Planet true-color mosaic with the polygonized perimeters (credited CC BY-NC 4.0), and a per-commune bar chart as SVG

Files: docs/blog/posts/sedonadb-raster.md plus two PNGs and one SVG.

How was this patch tested?

• Every number and console block comes from runs on the released sedonadb 0.4.1 wheel (pip install "apache-sedona[db]") against the public Planet, ESA WorldCover and Overture buckets named in the post; the pipeline was timed end to end from a cold process
• Polygon and zonal results were cross-checked against the imagery and against a second run with a different read strategy (identical to the pixel)
• pre-commit run --files on all four files passes; pre-commit run oxipng --hook-stage manual passes on the PNGs (second run clean); the post was rendered locally with mkdocs serve and every image, code block and the blog CTA checked

Did this PR include necessary documentation updates?

• Yes, I have updated the documentation.