refactor(bphtb): provide guided first-home template from GCS ## Changes MBR applicants need a clear format for the stamped first-home declaration. Provide a Word template based on the Surat Kuasa layout, with numbered fields and a separate Panduan Pengisian page. It includes the `NOPD PBB-P2` field, meterai area, applicant signature, and acknowledgement spaces for Kepala Desa/Lurah and Camat. Expose `Unduh Template Word` on the live MBR requirements summary and shared declaration page used by dasbor, Pajak Saya, and Kuasa Pajak. Download the fixed blank template from GCS through a server action and same-origin Blob, following the existing Kuasa pattern with pending and error states. The DOCX is not bundled in `public`. Closes #1885. ## Release impact Patch. Improve the existing MBR declaration workflow with a guided Word template and the application's existing GCS download pattern. ## Migration notes The template must exist at `gs://sapada-docs/template/Pernyataan Rumah Pertama MBR.docx` before deployment. It has been uploaded and verified with DOCX MIME and an attachment filename, using the same configured bucket as Surat Kuasa. GCS generation: `1793264572826542`. Size: 14,234 bytes. SHA-256: `6c0044b801fc6ce8af40439b68caa110849f0368cb8546bd7513e3ae9486a03e`. The existing public-bucket storage configuration is reused. No schema migration or new environment variable is needed. ## Validation - UI policy checks, targeted ESLint and Prettier passed against base `dfd5577ffde8ad40f50911df42a330d51176fa30`. - Changed-source React Doctor completed all selected checks across all 4 source files with 0 errors and 0 warnings; no skipped checks or projects. - Rendered and visually checked both final Word pages against the supplied Surat Kuasa. Confirmed all 17 numbered fields map to their guide entries, the reference page geometry and formatting parts are preserved, and the DOCX archive is valid. - Uploaded the GCS object with a create-only generation precondition, then downloaded it and verified that its SHA-256 matches the final local artifact. - Independent review and `git diff --check` passed. - Build, tests, and dev server were not run, per repository instructions.