Add EnsRainbowBeam app with endpoint for submitting labels

[djstrong]

Lite PR

Tip: Review docs on the ENSNode PR process

Summary

• Add EnsRainbowBeam (apps/ensrainbowbeam): Hono service with GET /health and POST /api/discover that labelhashes submitted label literals, classifies them against ENSNode’s Omnigraph labels index (unknown_in_index / healed_in_index / absent_from_index), skips unnormalizable labels, and emits one structured JSON line per submission to stdout (sink/storage deferred).
• Extend ENSApi Omnigraph with Query.labels(by: LabelsByLabelHashesInput!): LabelHash scalar, stricter validation, deduped batch lookup (cap 100 distinct hashes per request), plus codegen/SDK updates (enssdk, ensrainbow-sdk).
• Ship EnsRainbowBeamClient (@ensnode/ensrainbow-sdk/ensrainbowbeam-client), Docker/Compose (docker/services/ensrainbowbeam.yml), Terraform module (terraform/modules/ensrainbowbeam), broad CORS for browser use, and a Beam-it UI on docs/ensrainbow.io calling beam.ensrainbow.io.

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Why

• External callers need a small HTTP surface to submit label discoveries. Closes #2003.
• Batch labels lookup in ENSApi keeps Beam’s per-request Omnigraph traffic bounded and typed end-to-end.
• SDK + marketing-site UI make the endpoint usable from browsers and local dev immediately; JSONL stdout preserves a stable row shape for a future persistent/on-chain pipeline.

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Testing

• pnpm -F ensrainbowbeam test — 27 tests (labels.test.ts, submissions.test.ts: validation, classification, skipped unnormalized labels, Omnigraph timeout/error paths, JSONL logging).

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Notes for Reviewer (Optional)

• No persistence yet—stdout JSONL only; leaderboard/on-chain emission are follow-ups on Add new app with endpoint for submitting labels #2003.
• Per-request cap: 100 raw labels; each may expand to up to 2 distinct LabelHashes (raw + normalized). Omnigraph chunking uses LABELS_BY_LABELHASH_MAX (100).
• POST /api/discover body: { labels: string[], callerAddress: Address }; response includes per-label status, label, optional labelHash / normalizedLabel.
• CORS is origin: "*" (same pattern as other public ENSNode HTTP services)—not an env allowlist.
• Handler file is still named submissions.ts internally; public route is /api/discover.

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Pre-Review Checklist (Blocking)

• This PR does not introduce significant changes and is low-risk to review quickly.
• Relevant changesets are included (or are not required)