RubyGems still serves 0.1.3: release the staged 0.2.0 so consumers get the policy surface and the corpus

The repo sits at 0.2.0 staged but untagged; RubyGems still serves 0.1.3, which predates the `policy:` argument, the IPv6-allocated allowlist, and the shared conformance corpus (157 cases across 7 files, schema v1). Everything a consumer needs to enforce the two-policy contract is on the default branch and released nowhere.

The concrete consumer waiting on this: basecamp-sdk's Ruby OAuth enforcement (SPEC §16 requirements 5–6, tracked in its per-SDK issue) needs `Surfguard.resolve_public_ips` + the README's tested `Net::HTTP` `ipaddr=` pinning recipe against the 0.2.0 policy surface. That work is blocked at step 0 until the gem ships.

Asks:
- Tag and release the staged 0.2.0 gem to RubyGems.
- Confirm the README pinning recipe (`test/readme_recipe_test.rb`) is part of the released surface — the SDK will cite it as the enforcement pattern.

The Go module (`go/v0.1.0`) is already released and in use by basecamp-sdk; no action needed there.

Start by reviewing the staged 0.2.0 release on the default branch and the RubyGems release process. Run test/readme_recipe_test.rb to confirm the README pinning recipe is covered, then verify that the published 0.2.0 gem includes the tested policy surface and shared corpus.

Written by the indexing model from the issue text.