docs: add standardized gitlab templates and resolve vitest typing conflict

Summary

This MR introduces 8 standardized GitLab templates to streamline the contribution workflow and fixes a persistent TS2769 typing error in vite.config.ts to ensure the project passes full validation.

Closes #(issue_number)

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Implementation Details

GitLab Templates

• Created .gitlab/issue_templates/ and .gitlab/merge_request_templates/.
• Added feature_template.md, bug_fix_template.md, refactor_template.md, and doc_template.md to both directories.
• Templates include automated labels (e.g., /label ~"type::feature") and comprehensive quality checklists.

Config Fix

• Added /// <reference types="vitest" /> to vite.config.ts to extend the Vite UserConfig type with Vitest properties.
• Applied eslint-disable-next-line and explicit any types to the server.proxy.configure method to satisfy strict linting while maintaining functionality for proxying the Swecha API.

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Testing Strategy

Full suite run via npm run validate:

Check	Result
Files formatted	74
Files linted / type-checked	51
i18n validation	✅ Passed
Tests	✅ 166 passed

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Quality Checklist

• npm run format:check passes
• npm run lint passes
• npm run typecheck passes
• npm test passes
• CHANGELOG.md updated via npm run changelog
• No generated files or caches included in the diff.

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Closes #35 (closed)