feat: add tests and fixes for API documentation with interactive playground (#938) - #1032

…artdevs17#938)

- Add developer-portal/__tests__/apiDocumentation.test.ts with 35 tests
  covering DocumentationService (sections, articles, search, popular &
  related articles), DeveloperPortalService (developer registration,
  API key management, usage tracking, dashboard), and OpenAPI spec
  structure validation
- Fix missing DocumentationSection/DocumentationArticle type exports in
  developer-portal/types/portal.ts (was causing TS compilation errors)
- Add sandbox/services/sandboxService.ts stub to resolve broken import
  path in developerPortalService.ts
- Extend jest.backend.config.js to include developer-portal/__tests__
  in the backend test run

Technical scope: developer-portal/src/, developer-portal/docs/

The existing lock file had react-native@0.79.7 while package.json requires
0.85.2, plus several other mismatched/missing packages (metro, hermes, ws,
etc). Regenerated with npm install --legacy-peer-deps --package-lock-only
so that npm ci succeeds in CI.

Prettier (TypeScript Lint & Format):
- src/screens/CancellationFlowScreen.tsx: remove duplicate component
  definition fragment that caused a missing-brace parse error
- src/screens/SupportDashboardScreen.tsx: add missing closing </Card>
  and ) for renderMetric arrow function
- src/types/fraud.ts: remove dangling "| device-mismatch" line that
  was a leftover from a bad merge

TypeScript Type Check (contracts:codegen:check):
- Regenerate src/contracts/types/ with ethers-v5 typechain target so
  the committed output matches what npm run contracts:codegen produces

Rust Format Check:
- contracts/batch/src/batch.rs: create missing module file (declared
  via "mod batch;" in lib.rs but the file did not exist)
- contracts/subscription/src/gas_optimization.rs: remove duplicate
  inner-doc/attribute block that followed an outer doc comment
- contracts/subscription/src/gas_profiler.rs: same fix
- contracts/subscription/src/gas_storage.rs: remove duplicate import
  and misplaced inner attributes; reformat via cargo fmt
- contracts/credit/src/lib.rs: reformat via cargo fmt
- Run cargo fmt across all contracts

Merge conflict fix:
- backend/services/notification/alerting.ts: resolve unresolved
  conflict markers that blocked TypeScript compilation