[34/44] Enable TS strict mode in portlets-dot-query-tool-portlet

Description

Part of the strict-mode rollout epic #35932.

The original acceptance criteria were stale. They described a typescript-strict-plugin /
npx tsc-strict / @ts-strict-ignore approach that was dropped early in the epic. The approach
actually in force is in core-web/CLAUDE.md → TypeScript Strict Mode:
the six flags go in the project's own tsconfig.json, and tsconfig.base.json stays
"strict": false. Rewritten below to match.

Acceptance Criteria

• The six flags are in the project's own tsconfig.json:
  forceConsistentCasingInFileNames, strict, noImplicitOverride,
  noPropertyAccessFromIndexSignature, noImplicitReturns, noFallthroughCasesInSwitch.
• tsconfig.spec.json does not override them.
• tsc -p reports 0 on both the lib/app config and the spec config.
• No new any; no production non-null assertions added.
• nx run <project>:lint and :test pass.
• Blast radius verified across the strict projects.

Priority

Medium

Additional Context

Unblocked by edit-content (#35974) reaching 0. See the evidence comment below.

Start with the TypeScript Strict Mode section in core-web/CLAUDE.md, then inspect the portlets-dot-query-tool-portlet project's tsconfig.json and tsconfig.spec.json. Run tsc -p for both configurations, followed by the project's Nx lint and test targets; done means zero TypeScript errors, passing checks, no new any or production non-null assertions, and verified strict-project impact.