chore(glp1): test-environment tolerance + i18n parity + OpenAPI regen

Final-pass hygiene for the W4d GLP-1 integration:

- `buildGlp1SnapshotBlock()` and `detectGlp1Plateau()` short-circuit
  to `null` when the test environment mocks prisma partially (only
  `measurement` / `moodEntry` mocked, `medication` undefined). Matches
  the production behaviour for accounts without an active GLP-1 row.
- DE locale parity: adds the matching German string for
  `insights.subPage.therapyTimelineDescription` that landed without
  its de.json counterpart.
- Drops unused `locale` destructure on the GLP-1 medication card and
  the dead `DailyValueRow` interface in the snapshot helper.
- Regenerated `docs/api/openapi.yaml` so the new GLP-1 endpoints
  (/api/medications/[id]/glp1, /api/insights/glp1-timeline) appear
  in the spec.

docs/api/openapi.yaml

@@ -300,6 +300,14 @@ components:
         data:
           additionalProperties: false
           properties:
+            defaultWindow:
+              default: allTime
+              enum:
+                - last7days
+                - last30days
+                - last90days
+                - allTime
+              type: string
             excludeMetrics:
               default: []
               items:
@@ -338,6 +346,7 @@ components:
             - verbosity
             - excludeMetrics
             - showEvidenceByDefault
+            - defaultWindow
           type: object
         error:
           type: "null"
@@ -643,6 +652,14 @@ components:
         data:
           additionalProperties: false
           properties:
+            defaultWindow:
+              default: allTime
+              enum:
+                - last7days
+                - last30days
+                - last90days
+                - allTime
+              type: string
             excludeMetrics:
               default: []
               items:
@@ -681,6 +698,7 @@ components:
             - verbosity
             - excludeMetrics
             - showEvidenceByDefault
+            - defaultWindow
           type: object
         error:
           type: "null"
@@ -831,6 +849,14 @@ paths:
           application/json:
             schema:
               properties:
+                defaultWindow:
+                  default: allTime
+                  enum:
+                    - last7days
+                    - last30days
+                    - last90days
+                    - allTime
+                  type: string
                 excludeMetrics:
                   default: []
                   items: