docs(queryspace): surface current API contract

[fazpu]

Summary

Makes the already-shipped clean query-space cutover visible at the top of the public API reference.

• Adds a prominent current-contract notice naming the three assured operations.
• States that the 17 former patterns are examples.* saved queries, with no compatibility or deprecation layer.
• Corrects “Three things” to “Four things” for the four API guarantees already listed.

Important decisions

• This is an information-hierarchy correction, not a new documentation section or product contract.
• The existing detailed API, CLI, and MCP reference remains unchanged.

Sources inspected

• The deployed page at https://docs.remember.dev/docs/reference/api/
• Docs Site deployment run 31149590767 for refactor(queryspace): make clean pre-release cut #223
• website/src/app/docs/reference/api/page.mdx on main
• The public docs tree for stale dual-surface, compatibility, and deprecation language

Verification

• Confirmed the live site is serving the refactor(queryspace): make clean pre-release cut #223 deployment rather than stale cached output.
• git diff --check
• Site build and deployment are delegated to Docs Site CI.

Limitations and follow-up

• Content-only change; no API, design, or runtime behavior changes.
• No new navigation or documentation framework was introduced.

Contributor agreement

Signing on behalf of a legal entity (leave blank if accepting individually):

• I have read and agree to the RememberStack Contributor License Agreement v1.0.