fix(ci): repair submodule checkout and parser regressions

[M09Ic]

Summary

• point external/IoM-go at a published commit so Actions checkout can fetch submodules again
• add UnloadModule support to the command test recorder to match the updated RPC surface
• align packet-length expectations with current parser behavior and clean up malformed runtime connections

Validation

• go mod tidy
• go vet ./...
• go run ./scripts/testinventory -output dist/testing
• go test ./... -count=1 -timeout 300s
• CGO_ENABLED=0 go build ./...
• go test -race -count=1 -timeout 300s ./server/internal/core ./server/internal/parser/... ./server/internal/stream
• go test -tags=mockimplant ./server -count=1 -timeout 300s
• go test -tags=integration ./server ./client/command/listener ./client/command/pipeline ./client/command/website ./client/command/sessions ./client/command/context -count=1 -timeout 300s

Local act could not be completed because Docker is unavailable on this machine.

[M09Ic]

Superseded by #90, which includes the two CI repair commits plus the tagged-suite CI expansion and has already been merged into dev.