docs(volume_server): document rust-mode harness and tracking

test/volume_server/DEV_PLAN.md

@@ -1127,3 +1127,10 @@ Update this section during implementation:
 - Profiles covered: P1.
 - Gaps introduced/remaining: `499` cancellation and transport-interruption branches remain pending.
 - Commit: `d1e5f390a`
+
+- Date: 2026-02-15
+- Change: Added Rust volume-server migration bootstrap wiring.
+- APIs covered: Harness now supports Go master + selectable volume binary (`VOLUME_SERVER_IMPL=rust` or `VOLUME_SERVER_BINARY`), with Rust-mode smoke coverage for representative HTTP/gRPC integration tests.
+- Profiles covered: P1 smoke and default Go matrix unchanged.
+- Gaps introduced/remaining: native Rust handler implementations are tracked in `/Users/chris/dev/seaweedfs2/rust/volume_server/DEV_PLAN.md`; current Rust mode is a compatibility launcher phase.
+- Commit: pending

test/volume_server/Makefile

@@ -1,7 +1,10 @@
-.PHONY: test-volume-server test-volume-server-short
+.PHONY: test-volume-server test-volume-server-short test-volume-server-rust-smoke
 
 test-volume-server:
 	go test ./test/volume_server/... -v
 
 test-volume-server-short:
 	go test ./test/volume_server/... -short -v
+
+test-volume-server-rust-smoke:
+	VOLUME_SERVER_IMPL=rust go test ./test/volume_server/http ./test/volume_server/grpc -run 'TestAdminStatusAndHealthz|TestUploadReadRangeHeadDeleteRoundTrip|TestStateAndStatusRPCs|TestVolumeSyncStatusAndReadVolumeFileStatus' -v

test/volume_server/README.md

@@ -15,6 +15,9 @@ If a `weed` binary is not found, the harness will build one automatically.
 ## Optional environment variables
 
 - `WEED_BINARY`: explicit path to the `weed` executable (disables auto-build).
+- `VOLUME_SERVER_IMPL`: select volume-server implementation (`go` default, `rust` for Rust launcher mode).
+- `VOLUME_SERVER_BINARY`: explicit path to the volume-server executable (overrides `VOLUME_SERVER_IMPL`).
+- `VOLUME_SERVER_RUST_REBUILD=1`: force rebuild of Rust volume-server binary in Rust mode.
 - `VOLUME_SERVER_IT_KEEP_LOGS=1`: keep temporary test directories and process logs.
 
 ## Current scope (Phase 0)