feat(driver): host the driver v3/v4 streaming controller in sentio-core

[jupiterv2]

What

Adds the driver v3/v4 streaming controller to sentio-core — the engine that drives a processor over a chain block by block: fetch block data, run the processor's handlers, and persist ordered checkpoints (~21k LOC).

Design

Pipeline (main.go). MainController runs a three-stage concurrent pipeline over a block stream:

1. a producer builds per-block data and splits it into independent tasks;
2. a worker pool runs the handler tasks (concurrency configurable; seqMode forces single-worker ordering);
3. checkpoints are assembled strictly in block order and saved asynchronously.

Back-pressure is bounded by the waitingBlocks / progressNotice channels, so a slow handler or a slow checkpoint stage throttles fetching instead of growing memory unboundedly.

Run loop & resilience (main.go, errors.go). The loop classifies failures into ExternalError (driver vs. user-runtime) carrying an exit/retry Code, retries with backoff, and dedups repeated identical errors (gives up after a cap). Two internal signals — reorg detected and new template (dynamic data source) — restart the stream cleanly rather than erroring out.

Data layer (data/). Per-chain clients that fetch and normalize raw chain data — evm, aptos, sol, sui (+ sui/grpc), fuel — behind a common block/transaction abstraction, with block caching, interval sampling and subscribe support.

Fetcher (fetcher/). A generic concurrent fetch / merge / retry layer (FetchTarget / Requirement) the data layer uses to pull ranges in parallel and merge them back into ordered blocks.

Two handler models.

• standard/ — the SDK handler model: per-chain handlers (evm log/trace/transaction, aptos, sol instruction, sui event/change/function/interval, fuel) turn block data into binding-data tasks.
• subgraph/ — the WASM subgraph path: a wasm instance plus block/call/event handlers and its own block-data assembly.

Startup (startup/). Builds a ready-to-run controller from a processor model, wiring the checkpoint store, entity / timeseries stores, webhook publishing and quota tracking together.

Supporting libraries

• driver/controller/config — the per-chain ChainConfig + loaders.
• common/{compress,window,contract,jsonutils} and driver/exitcode (the process exit/retry Code type) — leaf libraries the controller needs.
• Adds the cloud.google.com/go/pubsub dependency (webhook pubsub topic).

Embedding seams

The controller stays free of binary-only packages and deployment values by taking its host integration through two interfaces it defines — controller.Notifier (callbacks the controller invokes at lifecycle and data events; what an implementation does with them is up to the caller) and startup.ClickhouseConnector (supplies the timeseries/entity chx.Controller) — plus an injected EntityMetricsMonitor and PubSubProject.

Test

• bazel build //driver/... — green.
• bazel test //driver/controller/... — 11/11 pass.