checker: fix ResumeBackend leaking goroutine on non-paused backend; v1.0.2

Calling ResumeBackend on a backend that wasn't actually paused (state
!= StatePaused) would overwrite w.cancel and spawn a fresh probe
goroutine without cancelling the old one, leaving two probe loops
running for the same backend until process exit. The guard now mirrors
EnableBackend's early-return on a non-target state.

Makefile

@@ -15,7 +15,7 @@ FRONTEND_WEB_SRC := $(shell find cmd/frontend/web/src -type f 2>/dev/null) \
 FRONTEND_WEB_DIST := cmd/frontend/web/dist/index.html
 
 NATIVE_ARCH  := $(shell go env GOARCH)
-VERSION      := 1.0.1
+VERSION      := 1.0.2
 COMMIT_HASH  := $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 DATE         := $(shell date -u +%Y-%m-%dT%H:%M:%SZ)
 LDFLAGS      := -X '$(MODULE)/cmd.version=$(VERSION)' \