chore: Regenerate weather/shapes projections + README cleanup

[jterapin]

Description

Regenerates the weather and shapes projections so generated clients pick up the Protocol plugin now that it's wired live (#349), and cleans up the README's helpful-commands section, which had drifted from the current rake task names.

Changes

• Projections: regenerated weather and shapes client/sig/spec files;
• README - fixed stale/broken references:
  • smithy:validate-fixtures no longer exists; smithy:sync-fixtures now validates inline.
  • smithy:spec doesn't exist; corrected to smithy:spec:unit.
  • Added the missing smithy:sync-protocol-tests task, with notes on how it pulls from the version-pinned smithy-protocol-tests Maven artifact and how to bump that pin.
  • Fixed the NoOpProtocol-style IRB example (Smithy::Client::RPCv2CBOR::Protocol → Smithy::Client::RpcV2Cbor, plus a required endpoint: option); verified it runs end-to-end.
  • Filled in missing gems (smithy-cbor, smithy-json, smithy-xml) in the spec/RBS command lists.
  • Fixed a broken apache-url link reference (badge linked nowhere).
• README - reorganized for scan-ability: Building Projections → IRB → Test Data (Fixtures / Protocol Tests) → Running Tests (Specs / RBS).

Testing

smithy-client:spec passes (852 examples, 0 failures, 2 pre-existing pending). Verified the updated IRB README snippet manually end-to-end (get_city/get_current_time return stubbed data).

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Written with AI assistance and reviewed by jterapin.