[12/44] Enable TS strict mode in sdk-react

Description

Part of the strict-mode rollout epic #35932. Enable TypeScript strict mode for the sdk-react project using typescript-strict-plugin.

• Dependency layer: 2 (0 = leaf library, 10 = top-level app)
• Internal dependents: 1 project(s)
• Rollout order: 12 / 44

All internal dependencies of sdk-react should already be in strict mode before starting (they appear earlier in the rollout order).

Acceptance Criteria

• All resulting type errors are resolved (no new any; use explicit types).
• // @ts-strict-ignore is used only where unavoidable, each with a follow-up TODO.
• yarn nx run sdk-react:lint passes (and :build / :test where applicable).
• npx tsc-strict passes for sdk-react.
• yarn nx affected -t build does not break dependents.

Priority

Medium

Additional Context

One project in the bottom-up rollout tracked by epic #35932. Depends on the bootstrap task being merged and on lower-layer projects already being strict.

Confirm the bootstrap task and lower-layer strict-mode dependencies from epic #35932 are complete, then inspect the sdk-react project configuration. Run npx tsc-strict and yarn nx run sdk-react:lint first; resolve the reported errors without new any types, document unavoidable strict ignores with TODOs, and verify build, tests, and affected dependents.