Add celestia blockchain type (Celestia DA JSON-RPC API)

[l0gun0v]

Adds the celestia blockchain type serving the Celestia DA node (celestia-node) JSON-RPC API — go-jsonrpc style namespaced methods (header.*, blob.*, share.*, das.*, blobstream.*).

Design

• json-rpc only (phase 1). celestia-node subscriptions use the go-jsonrpc channel protocol (xrpc.ch.val notifications), which the current ws parser treats as a malformed message and drops the connection. Head tracking is polling header.LocalHead. WS support needs a dedicated ws.WsProtocol implementation (follow-up).
• finalized == latest — CometBFT single-slot finality; the block processor (GenericBlockProcessor, safe-block detection off) publishes the head as the finalized pointer, like sui/stellar.
• Lower bound: BLOCK via header.Tail — the node reports its lowest stored header (DA sampling/pruning window) directly; one RPC per 2-minute refresh with a 3-attempt retry, no probing. Nodes older than v0.28 don't expose it: the detector errors every tick, no bound is published, the upstream is treated as archive.
• Method spec is read-only: 31 methods. blob.Submit / state.* writes are excluded (they spend TIA from the provider node's own wallet); node.*/p2p.* admin methods excluded; state.AccountAddress/state.Balance excluded (they expose the node's own wallet).
• No labels detector — node.Info requires an admin token.
• Chain ids are CometBFT strings (celestia / mocha-4), validated via header.LocalHead → .header.chain_id; any mismatch (empty id included) is FatalSettingError.
• ExtendedHeader is tmjson-encoded: height is a decimal string, hashes are bare hex — parsing is shared in specific_helpers.ParseCelestiaExtendedHeader.

Changes

• pkg/methods/specs/celestia.json: new plain spec, api-connectors: [json-rpc], 31 read methods, all cacheable: false
• pkg/chains/chains.go: Celestia blockchain type + celestia method-spec name mapping
• internal/upstreams/chains_specific/celestia_specific/celestia_chain_specific.go: ChainSpecific impl (head poll header.LocalHead, finalized == latest via GenericBlockProcessor, subscriptions rejected, labels/caps/methods processors nil)
• internal/upstreams/chains_specific/specific_helpers/celestia.go: shared ExtendedHeader parsing (+ tests)
• internal/upstreams/validations/celestia_validations/celestia_health_validator.go: health via node.Ready
• internal/upstreams/validations/celestia_validations/celestia_chain_validator.go: chain-id validation (any mismatch incl. empty id → FatalSettingError)
• internal/upstreams/lower_bounds/celestia_bounds/celestia_lower_bound.go: BLOCK bound via header.Tail, 2m period, 3 retries (+ tests)
• internal/upstreams/upstream_factory.go: dispatch case in getChainSpecific
• pkg/test_utils/test_helpers.go: NewCelestiaChainSpecific helper
• internal/upstreams/chains_specific/celestia_specific/celestia_chain_specific_test.go: parse/head/finalized/validators/processors tests
• docs/nodecore/11-method-specs.md, docs/nodecore/04-cache.md, docs/nodecore/05-upstream-config.md, README.md: shipped-specs table, cache blockchain-type list, validators/labels table rows, chain-family lists
• no submodule / generated-code changes: main already pins the emerald-grpc and chains.yaml revisions that carry celestia (1175/10209)

Testing

• unit: full ./internal/... ./pkg/... suite green (95 pkgs; docker-backed cache e2e need a daemon)
• live E2E against mocha (re-run on the rebased code, 2026-08-26): nodecore + local celestia light node (--rpc.skip-auth):
  • head polling works, supervisor State of CELESTIA-MOCHA: height=…, statuses=[AVAILABLE/1], bounds=[BLOCK=13571945]
  • header.GetByHeight / header.NetworkHead / das.SamplingStats / share.SharesAvailable OK
  • blob.GetAll returned 8 real blobs at height 13581002 (active rollup namespace)
  • excluded methods (blob.Submit, node.Info, unknown) → -32601 (spec acts as the allowlist)
  • height below Tail → upstream error passthrough requested header (100) is below Tail (13571945)

Notes

Rebased on current main (Sui, sub-responses refactoring). Implements the current ChainSpecific surface: CapDetectors/MethodsProcessor return nil (no ws transport, no method introspection on celestia-node).

Companion PRs: emerald-grpc, public, dproxy — linked in comments.

[l0gun0v]

Companion PRs: https://github.com/drpcorg/dproxy/pull/2829, drpcorg/emerald-grpc#168, drpcorg/public#246