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.

src/app/api/environment/home/route.ts

@@ -2,8 +2,8 @@
  * `PUT /api/environment/home` — set the account's coarse home location.
  *
  * The picked city (rounded lat/lon + label + IANA timezone) is stored on the
- * user. Coordinates are rounded to ~city granularity here as a defence-in-depth
- * floor even if a client sends finer values. Setting a home enqueues a
+ * user. Coordinates are rounded to 1 decimal (about 11 km) here as a
+ * defence-in-depth floor even if a client sends finer values. Setting a home enqueues a
  * lookback fetch so weather appears without waiting for the nightly tick.
  * Module-gated; `userId` is narrowed from auth.
  */

src/app/api/environment/travel/route.ts

@@ -3,7 +3,7 @@
  *
  * For any day in [startDate, endDate] the weather fetch resolves against this
  * coarse location instead of home (a declared trip dominates the home
- * fallback). Coordinates are rounded to ~city granularity. Adding an override
+ * fallback). Coordinates are rounded to 1 decimal (about 11 km). Adding an override
  * enqueues a lookback refresh so its days re-resolve. Module-gated; `userId` is
  * narrowed from auth.
  */