fix(privacy): store environment coordinates at 1 decimal instead of 2

The home location of the environment module was rounded to 2 decimals,
about 1 km, which places a home in a neighbourhood rather than the town the
schema comment promised. The weather archive it feeds is gridded at 9 to
25 km, so the extra precision bought nothing.

Every stored coordinate of the module now goes through the same 1-decimal
rounding (about 11 km north-south, 7 km east-west at 50° N): the home, the
travel periods, the geocoder's results, the per-day weather rows, and a
restore of a file written with finer values. Migration 0361 rounds the
existing users, travel periods and per-day rows; running it twice changes
nothing more. The answers keep their shape, plain numbers. The API
descriptions and the schema comment say 1 decimal now.

docs/api/openapi.yaml

@@ -20693,8 +20693,8 @@ paths:
         - Environment
       summary: Set the coarse home location
       description: >-
-        Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 2 dp server-side
-        regardless of what was sent.
+        Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 1 decimal (about 11 km)
+        server-side regardless of what was sent.
 
 
         Re-stamping is the part worth knowing: EVERY write moves `since` to now, including one that changes only the
@@ -20850,7 +20850,7 @@ paths:
       summary: Add a travel override
       description: >-
         Declares that the account was somewhere other than home for an inclusive date range; the days it covers resolve
-        against this location instead. Coordinates are rounded to 2 dp server-side.
+        against this location instead. Coordinates are rounded to 1 decimal (about 11 km) server-side.
 
 
         Adding one enqueues a refresh over exactly the declared window so its days re-resolve. Nothing checks for
@@ -72713,10 +72713,10 @@ components:
       properties:
         lat:
           type: number
-          description: Coarse latitude, rounded to 2 dp (~1 km).
+          description: Coarse latitude, rounded to 1 decimal (about 11 km).
         lon:
           type: number
-          description: Coarse longitude, rounded to 2 dp.
+          description: Coarse longitude, rounded to 1 decimal.
         label:
           anyOf:
             - type: string
@@ -72855,10 +72855,10 @@ components:
       properties:
         lat:
           type: number
-          description: Coarse latitude, rounded to 2 dp.
+          description: Coarse latitude, rounded to 1 decimal.
         lon:
           type: number
-          description: Coarse longitude, rounded to 2 dp.
+          description: Coarse longitude, rounded to 1 decimal.
         label:
           type: string
           description: Assembled from name, region and country, e.g. "City, Region, Country".