Fix v1.1.0 schema release blockers: verify ref, purchase duplicate-keys, authorize conditionality, requester clarification, duplicate-key guard

[GsCommand]

Motivation

• Resolve the known v1.1.0 release blockers and close the most visible schema-semantic drift without a broad refactor.
• Ensure the verify.receipt schema compiles under strict AJV and remove duplicate-key JSON artifacts that could mask intended stricter shapes.
• Tighten approval/denial semantics in authorize.receipt and clarify verify.request actor semantics so the contract is unambiguous.
• Add a lightweight guard to make duplicate-key regressions harder to reintroduce during validation.

Description

• Fixed schemas/v1.1.0/commercial/verify/verify.receipt.schema.json by pointing verifier to the existing #/$defs/verifier_actor so the verifier role remains typed and no broken internal $ref remains.
• Cleaned schemas/v1.1.0/commercial/purchase/purchase.receipt.schema.json by removing duplicate settlement and duplicate payment_proof definitions and leaving the stricter purchase-specific x402_proof shape as the active payment_proof contract.
• Resolved the example/schema mismatch by keeping the schema tight (no payment_ref added) so examples/v1.1.0/commercial/purchase/valid/900-purchase.receipt.valid.json validates against the corrected schema.
• Made authorization_id conditional in schemas/v1.1.0/commercial/authorize/authorize.receipt.schema.json so it is required for approved states and explicitly forbidden (along with other approval-only fields) in denied and pending states, preserving approved-state rigor.
• Clarified requester semantics in schemas/v1.1.0/commercial/verify/verify.request.schema.json and updated README.md and SPEC.md to state requester is an initiator slot (not a new governed actor role).
• Added a focused duplicate-key guard scripts/load-json-strict.mjs and wired it into scripts/validate-all.mjs and scripts/validate-examples.mjs so JSON files are scanned for duplicate keys before JSON.parse.
• Regenerated checksums.txt to reflect the changes to schemas and validation scripts.

Testing

• Ran npm run validate (which runs schema, example, and integrity checks) and it completed successfully.
• Ran npm run validate:examples and all example groups validated successfully.
• Compiled schemas/v1.1.0/commercial/verify/verify.receipt.schema.json with AJV under strict mode and compilation succeeded.
• Used the new strict JSON loader to parse schemas/v1.1.0/commercial/purchase/purchase.receipt.schema.json and examples/v1.1.0/commercial/purchase/valid/900-purchase.receipt.valid.json, both parsed/validated with no duplicate-key errors.

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Codex Task