worker: compile plugin.proto with the protoc that ships with the build

seaweed-volume already does this: protoc-bin-vendored carries the binary, so
the build needs no package manager and every build sees the same version. An
explicit PROTOC still wins, which is what lets the lance crates - whose own
build scripts read the same variable - share it.

Claude-Session: https://claude.ai/code/session_01Rkp1Mw5E89Jp6dzJFYiMrm

seaweed-worker/Cargo.lock

@@ -4666,6 +4666,70 @@ dependencies = [
  "prost 0.14.4",
 ]
 
+[[package]]
+name = "protoc-bin-vendored"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d1c381df33c98266b5f08186583660090a4ffa0889e76c7e9a5e175f645a67fa"
+dependencies = [
+ "protoc-bin-vendored-linux-aarch_64",
+ "protoc-bin-vendored-linux-ppcle_64",
+ "protoc-bin-vendored-linux-s390_64",
+ "protoc-bin-vendored-linux-x86_32",
+ "protoc-bin-vendored-linux-x86_64",
+ "protoc-bin-vendored-macos-aarch_64",
+ "protoc-bin-vendored-macos-x86_64",
+ "protoc-bin-vendored-win32",
+]
+
+[[package]]
+name = "protoc-bin-vendored-linux-aarch_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c350df4d49b5b9e3ca79f7e646fde2377b199e13cfa87320308397e1f37e1a4c"
+
+[[package]]
+name = "protoc-bin-vendored-linux-ppcle_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a55a63e6c7244f19b5c6393f025017eb5d793fd5467823a099740a7a4222440c"
+
+[[package]]
+name = "protoc-bin-vendored-linux-s390_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1dba5565db4288e935d5330a07c264a4ee8e4a5b4a4e6f4e83fad824cc32f3b0"
+
+[[package]]
+name = "protoc-bin-vendored-linux-x86_32"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8854774b24ee28b7868cd71dccaae8e02a2365e67a4a87a6cd11ee6cdbdf9cf5"
+
+[[package]]
+name = "protoc-bin-vendored-linux-x86_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b38b07546580df720fa464ce124c4b03630a6fb83e05c336fea2a241df7e5d78"
+
+[[package]]
+name = "protoc-bin-vendored-macos-aarch_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89278a9926ce312e51f1d999fee8825d324d603213344a9a706daa009f1d8092"
+
+[[package]]
+name = "protoc-bin-vendored-macos-x86_64"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81745feda7ccfb9471d7a4de888f0652e806d5795b61480605d4943176299756"
+
+[[package]]
+name = "protoc-bin-vendored-win32"
+version = "3.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95067976aca6421a523e491fce939a3e65249bac4b977adee0ee9771568e8aa3"
+
 [[package]]
 name = "quick-xml"
 version = "0.39.4"
@@ -5379,6 +5443,7 @@ dependencies = [
  "prometheus",
  "prost 0.13.5",
  "prost-types 0.13.5",
+ "protoc-bin-vendored",
  "tokio",
  "tokio-stream",
  "tonic",

seaweed-worker/crates/core/Cargo.toml

@@ -21,3 +21,7 @@ tracing.workspace = true
 
 [build-dependencies]
 tonic-build.workspace = true
+# Ships protoc with the build so neither CI nor a developer needs a system
+# install, and so the version is pinned rather than whatever the platform's
+# package manager happens to carry. The same crate seaweed-volume uses.
+protoc-bin-vendored = "3"

seaweed-worker/crates/core/build.rs

@@ -1,4 +1,12 @@
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Use the protoc that ships with protoc-bin-vendored rather than a system
+    // one, so the build needs no package manager and always sees the same
+    // version. An explicit PROTOC still wins, for packagers supplying their own
+    // and for the lance crates, whose own build scripts read the same variable.
+    if std::env::var_os("PROTOC").is_none() {
+        std::env::set_var("PROTOC", protoc_bin_vendored::protoc_bin_path()?);
+    }
+
     // Compiled straight out of the Go tree, the way seaweed-volume already reads
     // filer.proto, so the contract cannot drift from a vendored copy.
     tonic_build::configure()