feat(environment): add opt-in module, settings surface, API, and nightly fetch

Add the opt-in Environment module (default off), its Settings surface (home
location search, travel overrides, backfill, with Open-Meteo attribution), the
gated API routes (overview, home, geocode, travel CRUD, backfill), the nightly
pg-boss fetch job with a lookback window plus on-demand backfill, the query
keys, six-locale strings, and the regenerated OpenAPI. The module performs an
outbound weather fetch tied to a coarse location, so it ships dark and the user
turns it on deliberately; off means no job, no row, no egress.

docs/api/openapi.yaml

@@ -9737,6 +9737,8 @@ components:
           type: boolean
         doctorReport:
           type: boolean
+        environment:
+          type: boolean
         mcp:
           type: boolean
       additionalProperties: false
@@ -16775,6 +16777,9 @@ components:
         doctorReport:
           type: boolean
           description: Whether the "doctorReport" module is enabled for this account.
+        environment:
+          type: boolean
+          description: Whether the "environment" module is enabled for this account.
         mcp:
           type: boolean
           description: Whether the "mcp" module is enabled for this account.
@@ -16792,6 +16797,7 @@ components:
         - insights
         - medications
         - doctorReport
+        - environment
         - mcp
       additionalProperties: false
       description: Fully-resolved per-user module enable/disable map. Every toggleable module key is present. `false` means