Add event-bus-dto crate: shared envelope + schema generation

[jmg-duarte]

Description

Extracts the events into a separate crate so we can provide a JSONSchema for downstream usage (like analytics).
Generation style is similar to that of contracts, checks on CI are included.

Context: https://nomevlabs.slack.com/archives/C0B2X0Q7ERK/p1782315064424599

Related to BE-44

Changes

• Extract event types to a new crate
• Added JSONSchema generation

How to test

cargo r -p event-bus-dto

[claude]

Claude finished @jmg-duarte's task in 3m 23s —— View job

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PR Review: Add event-bus-dto crate

Reviewed the new crate, the schema-generation tooling, the CI check, and the migration out of observe / price-estimation. This is a clean, well-scoped refactor — the wire-format tests moved along with the types, the envelope logic is now single-sourced in Envelope::new, and the CI up-to-date check (git diff --exit-code) is logically correct.

Two non-blocking points posted inline:

• schemas() can silently drift — it's a hand-maintained list, so a new Event impl that isn't added here just won't appear in events.json, and CI won't catch it. (lib.rs:32)
• version isn't pinned in the schema — it's the field the envelope contract is built around, but the schema only says type: string. A schemars const/enum would make it machine-checkable. (envelope.rs:15)

Minor observations, not worth blocking on:

• observe::event_bus::publish is now only reached via publish_event; could be made private, but it's a reasonable public escape hatch for ad-hoc events.
• This adds schemars 1.2 while serde_with already pulls a (feature-gated) schemars 0.9, so two versions coexist in the graph. Fine given the crate is tiny.
• The Address→String change in emit_quote_event (from.to_string()) preserves the prior checksummed serialization, so no observable wire change.

Nice work — LGTM.

[gemini-code-assist]

Code Review

This pull request introduces a new event-bus-dto crate to centralize wire-format event types (DTOs) and their JSON schemas, separating them from the event producers. It extracts the Envelope and PriceEstimateEvent structures from the observe and price-estimation crates, and adds a schema generation binary (event-bus-schemas) along with a Justfile command to output the JSON schemas. The observe and price-estimation crates have been updated to use these shared types. No critical issues found.

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[linear-code]

BE-44