[13/44] Enable TS strict mode in sdk-analytics

Description

Part of the strict-mode rollout epic #35932. Enable TypeScript strict mode for the sdk-analytics project.

• Dependency layer: 2 (0 = leaf library, 10 = top-level app)
• Internal dependents: 0 project(s)
• Rollout order: 13 / 44
• Note: Isolated (0 dependents).

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

Note: the original acceptance criteria referenced typescript-strict-plugin, npx tsc-strict, and // @ts-strict-ignore. That approach was dropped by the epic — the plugin is not installed anywhere in the repo. The ACs below reflect the approach actually in force, documented in core-web/CLAUDE.md → TypeScript Strict Mode.

Acceptance Criteria

• The six strict flags are added to sdk-analytics's own tsconfig.json (not tsconfig.base.json, not tsconfig.spec.json):
  forceConsistentCasingInFileNames, strict, noImplicitOverride, noPropertyAccessFromIndexSignature, noImplicitReturns, noFallthroughCasesInSwitch.
• All resulting type errors are resolved (no new any; use explicit types).
• @ts-expect-error with a // TODO(#35946): note is used only where unavoidable — never a blanket @ts-ignore.
• pnpm exec tsc -p libs/sdk/analytics/tsconfig.lib.json --noEmit reports 0 errors.
• pnpm exec tsc -p libs/sdk/analytics/tsconfig.spec.json --noEmit reports 0 errors (the spec config extends tsconfig.json, so specs go strict too).
• nx run sdk-analytics:lint, :test, :build and :build:standalone pass.
• nx affected -t build,lint does not break dependents.
• The enforcement status is recorded — i.e. whether any CI gate actually verifies the strictness.

Priority

Medium

Additional Context

One project in the bottom-up rollout tracked by epic #35932.

Start with libs/sdk/analytics/tsconfig.json and review core-web/CLAUDE.md’s TypeScript Strict Mode guidance. Enable the six listed flags, then run the lib and spec tsc commands and the sdk-analytics lint, test, build, and build:standalone targets. Done means all type errors are resolved without new any, affected builds pass, and CI strictness enforcement is recorded.