Adds a fibremock package with:
- DA interface (Upload/Download/Listen) matching the fibre gRPC service
- In-memory MockDA implementation with LRU eviction and configurable retention
- Tests covering all paths

Migrated from celestiaorg/x402-risotto#16 as-is for integration.

Adds tools/celestia-node-fiber, a new Go sub-module that implements the
ev-node fiber.DA interface by delegating Upload, Download and Listen to a
celestia-node api/client.Client.

Upload and Download run locally against a Celestia consensus node (gRPC)
and Fibre Storage Providers (Fibre gRPC) — no bridge-node hop — using
celestia-node's self-sufficient client (celestiaorg/celestia-node#4961).
Listen subscribes to blob.Subscribe on a bridge node and forwards only
share-version-2 blobs, which is how Fibre blobs settle on-chain via
MsgPayForFibre.

The package lives in its own go.mod, parallel to tools/local-fiber, so
ev-node core does not inherit celestia-app / cosmos-sdk replace-directive
soup. A FromModules constructor accepts the Fibre and Blob Module
interfaces directly so callers can inject mocks or share an existing
*api/client.Client.

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>

…#3280)

* test(celestia-node-fiber): showcase end-to-end Upload/Listen/Download

Adds tools/celestia-node-fiber/testing/, a single-validator in-process
showcase that boots a fibre-tagged Celestia chain + in-process Fibre
server + celestia-node bridge, registers the validator's FSP via
valaddr (with the dns:/// URI scheme the client's gRPC resolver
expects), funds an escrow account, and drives the full adapter
surface.

TestShowcase proves the round-trip: subscribe via Listen, Upload a
blob, wait for the share-version-2 BlobEvent that lands after the
async MsgPayForFibre commits, assert the BlobID from Listen matches
Upload's return, Download and diff the payload bytes.

The harness is intentionally single-validator — a 2-validator
Docker Compose showcase is planned as a follow-up for exercising real
quorum collection.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

* test(celestia-node-fiber): scale showcase to 10 blobs, document DataSize gap

Upload 10 distinct-payload blobs through adapter.Upload, collect
BlobEvents via adapter.Listen until every BlobID is accounted for
(order-insensitive, rejects duplicates), then round-trip each blob
through adapter.Download to diff bytes. Catches routing bugs (wrong
blob returned for a BlobID) and duplicate-event bugs that a
single-blob test can't see.

Scaling the test also exposed a semantic issue: the v2 share carries
only (fibre_blob_version + commitment), so b.DataLen() — what
listen.go's fibreBlobToEvent reports today — is always 36, not the
original payload length ev-node's fibermock conveys. The adapter
can't derive the payload size from the subscription stream alone;
surfacing it correctly needs an x/fibre PaymentPromise lookup
(tracked as a TODO on fibreBlobToEvent). The test therefore asserts
DataSize is non-zero rather than matching len(payload).

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>

…3281)

listen.go previously set BlobEvent.DataSize to b.DataLen(), which for
a share-version-2 Fibre blob is always the fixed share-data layout
(fibre_blob_version + commitment = 36 bytes) — not the original
payload length. That diverges from ev-node's fibermock contract and
misleads any consumer that uses DataSize to allocate buffers or
report progress.

The v2 share genuinely doesn't carry the original size, and x/fibre
v8 has no chain query to derive it from the commitment. The only
accurate path is to Download the blob and measure. Listen now does
exactly that before forwarding each event. The cost is one FSP
round-trip per v2 blob; can be made opt-out later if it hurts
throughput-sensitive use cases.

Tests:
- Showcase restores the strict DataSize == len(payload) assertion
  across all 10 blobs.
- Unit test TestListen_FiltersFibreOnlyAndEmitsEvent now stubs
  fakeFibre.Download to return a deterministic payload and asserts
  DataSize matches its length.

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>

…ight subscriptions (#3283)

feat(celestia-node-fiber): Listen takes fromHeight for resume subscriptions

Threads a fromHeight parameter through the Fibre DA Listen path so a
subscriber can rejoin the stream from a past block height without
missing blobs. Consumes the matching celestia-node API change landed
in celestiaorg/celestia-node#4962, which gave Blob.Subscribe a
fromHeight argument backed by a WaitForHeight loop.

Changes:

- block/internal/da/fiber/types.go: DA.Listen signature now takes
  fromHeight uint64. fromHeight == 0 preserves "follow from tip"
  semantics, >0 replays from that block forward.
- block/internal/da/fibremock/mock.go: replay matching blobs with
  height >= fromHeight before attaching the live subscriber.
- block/internal/da/fiber_client.go: outer fiberDAClient.Subscribe
  does not yet expose a starting height (datypes.DA doesn't plumb
  one), so pass 0 and defer resume-from-height wiring to a future
  datypes.DA change.
- tools/celestia-node-fiber/listen.go: propagate fromHeight to
  client.Blob.Subscribe on the celestia-node API.
- tools/celestia-node-fiber/go.mod: bump celestia-node to the merged
  pseudo-version (v0.0.0-20260423143400-194cc74ce99c) carrying #4962.
- tools/celestia-node-fiber/adapter_test.go: fakeBlob.subscribeFn
  gets the new fromHeight arg; TestListen_FiltersFibreOnlyAndEmitsEvent
  asserts that fromHeight=0 is forwarded.
- tools/celestia-node-fiber/testing/showcase_test.go: existing
  TestShowcase passes fromHeight=0. New TestShowcaseResume uploads 3
  blobs, discovers their settlement heights via a live Listen, then
  opens a fresh Listen with fromHeight at the first blob's height and
  verifies every historical blob is replayed with correct Height and
  DataSize.

Co-authored-by: Claude Opus 4.7 (1M context) <[email protected]>