fix(evidence): year dropdown default val as array

defaultValue arg of Dropdown component only accepts a string or an array
(a buggy thing), so this makes it work and default to the most recent
year.

reports/pages/index.md

@@ -47,7 +47,7 @@ order by count_of_trees desc
   name="trees_planted_years"
   data={trees_planted_years}
   value="year"
-  defaultValue={2024}
+  defaultValue={[trees_planted_years[0].year]}
 />
 
 <CalendarHeatmap
@@ -78,7 +78,7 @@ group by 1
 
 ```sql trees_planted_years
 select
-  distinct date_part('year', planted_at_date)::int as year
+  distinct date_part('year', planted_at_date) as "year"
 
 from dbtree.trees