Refactor TinyBus contract into a crate

.github/workflows/release.yml

@@ -129,8 +129,8 @@ jobs:
  NEXT_VERSION: ${{ steps.version.outputs.next_version }}
  run: |
  set -euo pipefail
- perl -0pi -e 's/(\[package\][\s\S]*?\nversion = ")[^"]+(")/$1$ENV{NEXT_VERSION}$2/' Cargo.toml
-perl -0pi -e 's/(\[package\][\s\S]*?\nversion = ")[^"]+(")/$1$ENV{NEXT_VERSION}$2/' crates/tinydocs-module/Cargo.toml
+ perl -0pi -e 's/(\[workspace\.package\][\s\S]*?\nversion = ")[^"]+(")/$1$ENV{NEXT_VERSION}$2/' Cargo.toml
+cargo update -p tinydocs-bus --precise "$NEXT_VERSION"
  cargo update -p "$CRATE_NAME" --precise "$NEXT_VERSION"
 
  - name: Commit version bump and tag
@@ -140,12 +140,21 @@ jobs:
  set -euo pipefail
  git config user.name "github-actions[bot]"
  git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
- git add Cargo.toml Cargo.lock crates/tinydocs-module/Cargo.toml
+ git add Cargo.toml Cargo.lock
  git commit -m "Release ${RELEASE_TAG}"
  git tag -a "${RELEASE_TAG}" -m "Release ${RELEASE_TAG}"
 
- - name: Package crate
- run: cargo package --locked --package tinydocs
+ - name: Package and publish the bus contract
+ run: |
+ set -euo pipefail
+ cargo package --locked --package tinydocs-bus
+ cargo publish --locked --package tinydocs-bus
+
+ - name: Package and publish crate
+ run: |
+ set -euo pipefail
+ cargo package --locked --package tinydocs
+ cargo publish --locked --package tinydocs
 
  - name: Package TinyBus source and module SDK
  run: |
@@ -162,6 +171,7 @@ jobs:
  with:
  name: source-packages
  path: |
+ target/package/tinydocs-bus-${{ steps.version.outputs.next_version }}.crate
  target/package/${{ steps.version.outputs.crate_name }}-${{ steps.version.outputs.next_version }}.crate
  target/package/tinybus-source-*.tar.gz
  if-no-files-found: error

AGENTS.md

@@ -32,13 +32,13 @@ This is a Rust 2024 library crate rooted at `Cargo.toml`.
 ```text
 src/
 ├── lib.rs # crate docs + the entire public re-export surface
-├── error/mod.rs # crate-wide `Error` and `Result<T>`
 └── <feature>/ # one directory per feature area
  ├── mod.rs # module docs, wiring, smallest useful public API
  ├── types.rs # substantial type definitions
  └── test.rs # module-local unit tests
 tests/ # integration tests against the public API only
 examples/ # runnable, compiled-in-CI usage examples
+crates/tinydocs-bus/ # TinyBus wire contract: names, payload types, errors
 crates/tinydocs-module/ # private TinyBus cdylib adapter
 vendor/tinybus/ # pinned TinyBus source; optional until wired by a project
 docs/
@@ -64,8 +64,9 @@ missing module. Prefer many small modules that each do one thing well over few
 broad ones.
 
 Keep public exports centralized in `src/lib.rs` so downstream users have one
-predictable surface. Put shared error variants in `src/error/mod.rs` and return
-the crate-wide `Result<T>` from fallible public APIs.
+predictable surface. The shared error variants live in `tinydocs-bus` because
+`DocumentSpec::validate` is an inherent method on a contract-owned type; re-
+export its `Error` and `Result<T>` from `src/lib.rs` for the primary API.
 
 ## Build And Test
 
@@ -114,8 +115,9 @@ Use standard `rustfmt` output and Rust 2024 idioms. Do not hand-format around
 
 ### Errors
 
-- One crate-wide `Error` enum in `src/error/mod.rs`, built with `thiserror`.
-- Fallible public functions return `Result<T>`, the crate alias.
+- One crate-wide `Error` enum in `crates/tinydocs-bus/src/error/mod.rs`, built with
+ `thiserror` and re-exported by `tinydocs`.
+- Fallible public functions return `Result<T>`, the re-exported crate alias.
 - Add a specific variant instead of stuffing context into a string; error
  messages are lowercase, without trailing punctuation.
 - Do not `unwrap()`, `expect()`, or `panic!` in library code paths. They are