3 modules fail to build at main: missing go.sum entry for btcsuite bech32 (go-nostr nip19) #990

Found while verifying #989 (see its battery evidence): at origin/main 9e4702e, three modules fail go build/go test identically:

/home/user/go/pkg/mod/github.com/nbd-wtf/go-nostr@v0.51.12/nip19/nip19.go:9:2:
missing go.sum entry for module providing package
github.com/btcsuite/btcd/btcutil/bech32 (imported by github.com/nbd-wtf/go-nostr/nip19);
to add: go get github.com/nbd-wtf/go-nostr/nip19@v0.51.12

Affected: src/merchant_types, src/upstream_detector, src/upstream_session_manager.

Their go.sum files were last touched by #681's deps sweep; the entry for btcsuite/btcd/btcutil/bech32 (pulled in via go-nostr@v0.51.12/nip19) is missing in exactly these three carriers. With the Actions org-freeze (#790) nothing exercised these module builds since, which is also the class of blind spot #989's make test runner makes cheaper to check (per-module invocation from any checkout).

Fix shape per the drift doctrine: the missing entries are per-module go.sum facts — regenerate with go mod tidy inside each affected module (or a single-pin bump through the existing tooling if gonuts-adjacent), then make go-battery (14 other modules are green at the same SHA).