feat: separate proto files into standalone crate

Extract protocol buffer definitions into a separate `snapchain-proto`
crate so consumers can import protos without depending on the entire
snapchain project.

Changes:
- Create `proto/` workspace member with its own Cargo.toml and build.rs
- Move proto definitions from `src/proto/` to `proto/definitions/`
- Move proto-only impls (Height, ShardHash, Message, etc.) to proto crate
- Add extension traits for methods requiring main crate types:
  - CommitsExt for commit certificate conversion
  - FullProposalExt for proposer address
  - HubEventExt for event construction
  - HubEventStorageExt for storage operations
- Update imports throughout codebase to use extension traits
- Rename HubEvent::from() to HubEvent::new_event() to avoid trait conflict

Author: christopherwxyz

Cargo.lock

@@ -1,3 +1,7 @@
+[workspace]
+members = ["proto"]
+resolver = "2"
+
 [package]
 name = "snapchain"
 version = "0.11.0"
@@ -7,7 +11,9 @@ default-run = "snapchain"
 [lib]
 name = "snapchain"
 path = "src/lib.rs"
+
 [dependencies]
+snapchain-proto = { path = "proto" }
 tokio = { version = "1.40.0", features = ["full"] }
 tokio-stream = "0.1"
 serde = { version = "1.0", features = ["derive"] }
@@ -98,8 +104,6 @@ solar-macros = "=0.1.1"
 solar-config = "=0.1.1"
 nix = { version = "0.29", features = ["resource"] }
 
-[build-dependencies]
-tonic-build = "0.9.2"
 
 [dev-dependencies]
 serial_test = "3.1.1"
@@ -108,3 +112,4 @@ insta = { version = "1.40", features = ["json"] }
 
 [package.metadata.precommit]
 fmt = "cargo fmt --check --quiet"
+

Cargo.toml

@@ -30,7 +30,8 @@ EOF
 # since the Cargo configuration references files in src.
 # This means we'll re-fetch all crates every time the source code changes,
 # which isn't ideal.
-COPY Cargo.lock Cargo.toml build.rs ./
+COPY Cargo.lock Cargo.toml ./
+COPY proto ./proto
 COPY src ./src
 
 ENV RUST_BACKTRACE=full
@@ -59,7 +60,7 @@ RUN <<EOF
 EOF
 
 WORKDIR /app
-COPY --from=builder /usr/src/app/src/proto /app/proto
+COPY --from=builder /usr/src/app/proto/definitions /app/proto
 COPY --from=builder /usr/src/app/nodes /app/nodes
 COPY --from=builder \
   /usr/src/app/target/release/snapchain \

Dockerfile

@@ -0,0 +1,17 @@
+[package]
+name = "snapchain-proto"
+version = "0.11.0"
+edition = "2021"
+description = "Protocol buffer definitions for Snapchain"
+license = "MIT"
+
+[dependencies]
+prost = "0.13.3"
+tonic = { version = "0.12.3", features = ["tls", "tls-native-roots"] }
+serde = { version = "1.0", features = ["derive"] }
+futures-core = "0.3.31"
+hex = "0.4.3"
+informalsystems-malachitebft-core-types = { path = "../../malachite/code/crates/core-types" }
+
+[build-dependencies]
+tonic-build = "0.9.2"

proto/Cargo.toml

@@ -11,20 +11,20 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     // TODO: auto-discover proto files
     builder.compile(
         &[
-            "src/proto/admin_rpc.proto",
-            "src/proto/blocks.proto",
-            "src/proto/rpc.proto",
-            "src/proto/message.proto",
-            "src/proto/onchain_event.proto",
-            "src/proto/hub_event.proto",
-            "src/proto/username_proof.proto",
-            "src/proto/sync_trie.proto",
-            "src/proto/node_state.proto",
-            "src/proto/gossip.proto",
-            "src/proto/request_response.proto",
-            "src/proto/replication.proto",
+            "definitions/admin_rpc.proto",
+            "definitions/blocks.proto",
+            "definitions/rpc.proto",
+            "definitions/message.proto",
+            "definitions/onchain_event.proto",
+            "definitions/hub_event.proto",
+            "definitions/username_proof.proto",
+            "definitions/sync_trie.proto",
+            "definitions/node_state.proto",
+            "definitions/gossip.proto",
+            "definitions/request_response.proto",
+            "definitions/replication.proto",
         ],
-        &["src/proto"],
+        &["definitions"],
     )?;
 
     Ok(())