Add regional task templates API with climate zone lookup

Adds a new endpoint GET /api/tasks/templates/by-region/?zip= that resolves
ZIP codes to IECC climate regions and returns relevant home maintenance
task templates. Includes climate region model, region lookup service with
tests, seed data for all 8 climate zones with 50+ templates, and OpenAPI spec.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/openapi.yaml

@@ -523,6 +523,39 @@ paths:
                 items:
                   $ref: '#/components/schemas/TaskTemplateResponse'
 
+  /tasks/templates/by-region/:
+    get:
+      tags: [Static Data]
+      operationId: getTaskTemplatesByRegion
+      summary: Get task templates for a climate region by state or ZIP code
+      description: Returns templates matching the climate zone for a given US state abbreviation or ZIP code. At least one parameter is required. If both are provided, state takes priority.
+      parameters:
+        - name: state
+          in: query
+          required: false
+          schema:
+            type: string
+            example: MA
+          description: US state abbreviation (e.g., MA, FL, TX)
+        - name: zip
+          in: query
+          required: false
+          schema:
+            type: string
+            example: "02101"
+          description: US ZIP code (resolved to state on the server)
+      responses:
+        '200':
+          description: Regional templates for the climate zone
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/TaskTemplateResponse'
+        '400':
+          $ref: '#/components/responses/BadRequest'
+
   /tasks/templates/{id}/:
     get:
       tags: [Static Data]