[runtime] sync docs to v1.1.0 runtime cut

[GsCommand]

Motivation

• Bring runtime-layer documentation into alignment with the implemented behavior in server.mjs for the v1.1.0 cut (route version, fabricated x402 defaults, and schema validation targets).
• Avoid continuing to document the live runtime as v1.0.0 and prevent stale guidance about schema resolution and x402 defaults.

Description

• Updated README.md to reference the live verb routes as POST /<verb>/v1.1.0, state that schema validation targets the v1.1.0 receipt schema tree under SCHEMA_HOST, and document that the runtime fabricates x402.version and x402.entry defaults using the live API version (1.1.0) when callers omit x402.
• Updated docs/CONFIGURATION.md to change API_VERSION references to 1.1.0, document the fabricated x402 defaults for omitted request metadata, and state that SCHEMA_HOST is used to construct v1.1.0 receipt schema URLs during /verify?schema=1.
• Updated docs/OPERATIONS.md to describe the active POST /<verb>/v1.1.0 routes, the fabricated x402 defaults behavior, and that schema warmup/validation targets the v1.1.0 schema path.
• Updated SECURITY.md supported versions entry to 1.1.x and added a narrowly scoped note about schema resolution targeting v1.1.0 and the fabricated x402 defaults; no changes to signing/ENS claims were introduced.
• This is a documentation-only change set; no runtime code or endpoints were added or removed.

Testing

• Ran repository unit and smoke tests via npm test; all tests passed (unit tests and tests/smoke.mjs completed successfully).
• Ran targeted grep checks to confirm no remaining v1.0.0 references in the modified doc files and validated the committed diff.
• Changes committed with a commit message following the repo guidance (why + contract impact).

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Codex Task