FireBAT Map: Colour the thessian polygon

**As a** *FBAN* **I want** *to see an orange polygon surrounding a weather station when it crosses 4,000 kw/m or red polygon surrounding a station when it crosses 10,000 kw/m* **So That** *I can clearly, quickly see the affected areas under advisory or extreme warning on a map, and easily differentiate the two advisory-types from other information on the map*

**Additional Context**
- re: estimation: we could slice this up
- AC pts 1-2: dev 1
- AC pts 3-6: dev 2
- FYI ONLY, NOT MVP: it would be absolutely epic to see what kind of interpolation or smoothing is possible - users are bringing this up A LOT. Keep it in the back of your mind, we'll watch for this as we test the proto.
-- this is an oversimplification BUT broad advisory areas (err on the side of caution) may be preferred over 'polka dot maps' (little advisory areas sprinkled around the map that are very close to one another) or jagged shapes drawn around a weather station (what is the actual boundary around a weather station, where does the risk end?) - for discussion and further exploration

**Acceptance Criteria**
- [ ] Given I am using FireBAT, When I select a Fire Centre, Then I only see coloured polygons for station and fuel combos that are 4,000+ on the map
- [ ] Given I am using FireBAT, When I have selected my Fire Centre, Then any station-fuel combinations that cross a 4,000 threshold are filled in orange with opacity to the base layer is visible
- [ ] Given I am using FireBAT, When I have selected my Fire Centre, Then any station-fuel combinations that cross a 10,000 threshold are filled in red with opacity to the base layer is visible
- [ ] Given I am using FireBAT, When I have selected my Fire Centre, Then any station-fuel combinations that are close to my Fire Centre boundary and are crossing an HFI threshold are also visible to me
- [ ] Given we cannot calculate for a given station, we display a black polygon on the map
- [ ] Given I am using FireBAT, When I look at an area of the map with coloured polygons, Then I can still see the base layer of the map to orient myself (polygon is not filled, not obscuring the map context, labels are visible)

**Definition of Done**
- [ ] Ready to Demo in Sprint Review
- [ ] Does what I have made have appropriate test coverage?
- [ ] Documentation and/or scientific documentation exists and can be found
- [ ] Peer Reviewed by 2 people on the team
- [ ] Manual testing of all PRs in Dev and Prod
- [ ] Merged

Start in FireBAT by selecting a Fire Centre and observing station/fuel combinations on the map. Verify the 4,000 and 10,000 thresholds, boundary-adjacent stations, unavailable calculations, and polygon opacity against the acceptance criteria. Done means the coloured or black polygons preserve the base map context and the listed documentation, testing, and review requirements are complete.

Written by the indexing model from the issue text.