Prepare @workit/core 0.3.0 time-policy release

[AdmilsonCossa]

Summary

Prepare @workit/core 0.3.0 with the additive @workit/core/time-policy public subpath.

• Adds planTimePolicy(), estimateRetry(), and estimateHedge() for declared retry, hedge, timeout, deadline, series, and parallel time-policy planning.
• Wires ESM, CommonJS, strict TypeScript, API-surface, CJS build, package-consumer, and npm README coverage for the new subpath.
• Adds bounded correctness evidence for retry/deadline planning, a finite time-policy cost model, and nested composition rules.
• Bumps root and package versions to 0.3.0 and updates changelog/citation docs.

Validation

• npm --workspace @workit/core run build
• npx vitest run packages/core/tests/unit/time-policy.test.js
• node packages/core/tests/evidence/correctness/time-policy-planner.mjs
• node packages/core/tests/evidence/correctness/formal-time-policy-model.mjs
• node packages/core/tests/evidence/correctness/nested-time-policy-composition.mjs
• npm --workspace @workit/core run check:api
• npm --workspace @workit/core run check:package-consumer
• npm run test:coverage
• npm run test:evidence
• npm run bench:articles
• npm run verify
• npm --workspace @workit/core run check:release