Sync ERC-8262.md with upstream + keep F-2/F-3 deltas

[DROOdotFOO]

Summary

The repo's ERC-8262.md had fallen 187 lines behind the upstream ../ERCs/ERCS/erc-8262.md submitted to ethereum/ERCs#1747. This PR brings the two into sync and preserves the F-2/F-3 normative deltas just landed in #14.

Sections pulled from upstream

• Proof System Requirements (128-bit security floor, named systems)
• Circuit Conventions (constants table, value ranges, public-input encoding, active-slot semantics, domain-tag distinctness, threshold lookup helper)
• Commitment Layouts (H_provider_set, H_config, H_tx_set, H_credential, Merkle leaves, H_signed, H_multi_slot, H_signer_pubkey)
• Per-Type Circuit Specifications (numbered constraint lists per circuit, all nine proof types)
• Batch Verification Limits (MAX_BATCH_SIZE = 10 rationale)
• Proof Hash Computation (the normative replay-protection text)
• Circuit Constraints (cross-cutting timestamp + submitter rules)
• Pause Mechanism, Administrative Operations, Trust Tier Disclosure

F-2 / F-3 deltas kept from #14

• Jurisdiction Policy subsection (requireSignedSignals + minMultiProviderThreshold table with MUST language)
• pattern.settlement_root MUST mark + canonical computation
• Three "see Jurisdiction Policy" cross-refs replacing scattered "e.g. US BSA, Singapore" asides

F-1 (UAE) was already in upstream. F-4 (proofHash forward-ref) was already in upstream as the -- see Proof Hash Computation comment.

After this lands

Both files are byte-equal except for the three F-2 / F-3 deltas this repo carries. The companion PR (xochi-fi/ERCs side) pushes the same deltas to upstream; after that PR, the files match exactly.

Manual testing

• python3 scripts/eip-interface-drift.py -- clean (interface signatures unchanged)
• forge fmt --check -- clean
• forge build -- clean (no Solidity touched)