chore: fix Justfile refs

Turns out using {{X}} in a global doesn't trigger interpolation. This resulted
in files like the literal `{{CONSOLE_ROOT}}/foo/bar`, which don't exist, being
used for dependency checks, triggering rebuilds on every invocation.

In particular this would trigger proto rebuils and console rebuilds, the latter
of which was quite time consuming :\

Justfile

@@ -8,10 +8,10 @@ TIMESTAMP := `date +%s`
 SCHEMA_OUT := "backend/protos/xyz/block/ftl/v1/schema/schema.proto"
 ZIP_DIRS := "go-runtime/compile/build-template go-runtime/compile/external-module-template go-runtime/compile/main-work-template internal/projectinit/scaffolding go-runtime/scaffolding jvm-runtime/java/scaffolding jvm-runtime/kotlin/scaffolding"
 CONSOLE_ROOT := "frontend/console"
-FRONTEND_OUT := "frontend/console/dist/index.html"
+FRONTEND_OUT := CONSOLE_ROOT + "/dist/index.html"
 EXTENSION_OUT := "frontend/vscode/dist/extension.js"
 PROTOS_IN := "backend/protos/xyz/block/ftl/v1/schema/schema.proto backend/protos/xyz/block/ftl/v1/console/console.proto backend/protos/xyz/block/ftl/v1/ftl.proto backend/protos/xyz/block/ftl/v1/schema/runtime.proto"
-PROTOS_OUT := "backend/protos/xyz/block/ftl/v1/console/console.pb.go backend/protos/xyz/block/ftl/v1/ftl.pb.go backend/protos/xyz/block/ftl/v1/schema/runtime.pb.go backend/protos/xyz/block/ftl/v1/schema/schema.pb.go {{CONSOLE_ROOT}}/src/protos/xyz/block/ftl/v1/console/console_pb.ts {{CONSOLE_ROOT}}/src/protos/xyz/block/ftl/v1/ftl_pb.ts {{CONSOLE_ROOT}}/src/protos/xyz/block/ftl/v1/schema/runtime_pb.ts {{CONSOLE_ROOT}}/src/protos/xyz/block/ftl/v1/schema/schema_pb.ts"
+PROTOS_OUT := "backend/protos/xyz/block/ftl/v1/console/console.pb.go backend/protos/xyz/block/ftl/v1/ftl.pb.go backend/protos/xyz/block/ftl/v1/schema/runtime.pb.go backend/protos/xyz/block/ftl/v1/schema/schema.pb.go " + CONSOLE_ROOT + "/src/protos/xyz/block/ftl/v1/console/console_pb.ts " + CONSOLE_ROOT + "/src/protos/xyz/block/ftl/v1/ftl_pb.ts " + CONSOLE_ROOT + "/src/protos/xyz/block/ftl/v1/schema/runtime_pb.ts " + CONSOLE_ROOT + "/src/protos/xyz/block/ftl/v1/schema/schema_pb.ts"
 
 _help:
   @just -l