chore(schema): sync proof bundle schema

[andymolecule]

Context

Agora PR #1010 adds peer snapshot commitments to proof bundles for issue #998. Agora's cross-repo runtime schema verifier now expects proof_bundle sha256 a3ad90c5655f32140c31d05d21b9f379bee6d501cc59b2e9c4e96517d355d942.

Change

• Revendor schema/proof-bundle.canonical.schema.json from the Agora implementation branch.
• Update schema/proof-bundle.canonical.sha256 to the matching canonical hash.

Validation

• git diff --check
• npm ci
• npm test
• npm run check:replay-boundary
• npm run check:release-provenance
• AGORA_MAIN_RUNTIME_MANIFEST_SCHEMA_PATH=/private/tmp/agora-agent-worktrees/issue-998-add-deadline-peer-snapshot-fasta-novelty-for-corpus-simi/packages/common/src/schemas/scorer-runtime-manifest.canonical.schema.json AGORA_MAIN_PROOF_BUNDLE_SCHEMA_PATH=/private/tmp/agora-agent-worktrees/issue-998-add-deadline-peer-snapshot-fasta-novelty-for-corpus-simi/packages/common/src/schemas/proof-bundle.canonical.schema.json npm run check:agora-main-schema-sync
• AGORA_SCORER_REPO_ROOT=/tmp/agora-scorers-proof-sync pnpm runtime-schema:verify-cross-repo (from the Agora PR worktree)

Merge Order

Merge this before expecting Agora PR #1010 runtime-golden/guardrail checks to pass.