v0.1.0

• release: relicense under Apache-2.0 and cut v0.1.0
• docs: expand README into a detailed guide; demo Remember in examples
• feat: add optional background expiry sweeper + Close
• feat: add single-flight Remember
• docs: add Use cases section + per-key rate limiter and template recipes
• feat!: make OnEvict value-bearing
• docs: add README recipes; note value-bearing OnEvict + Remember as open items
• feat: initial release of cache-obj