fix(lint): gocritic/unparam/unused + migration renumber in notifications PR

Address four linter findings in the mute/unsubscribe feature:
- smtp_sender: use %q instead of escaped-quote "%s" (sprintfQuotedString)
- sender: remove unused mailtoURL return from buildUnsubscribeURL (unparam)
- templates: remove dead sendPurchaseApprovalRequestVia function (unused)
- migration: renumber 000078_muted_recipients to 000091 to resolve
  conflict with 000078_monthly_summary_nested_rollup already on main

Author: cristim

internal/config/interfaces.go

@@ -437,7 +437,7 @@ type StoreInterface interface {
 	LatestLadderRunStartedAt(ctx context.Context, configID string) (*time.Time, error)
 	TransitionLadderRunStatus(ctx context.Context, id string, fromStatuses []ladder.RunStatus, toStatus ladder.RunStatus) (*LadderRunDB, error)
 
-	// Notification mutes (issue #297 / migration 000078).
+	// Notification mutes (issue #297 / migration 000091).
 	// UpsertNotificationMute inserts or updates a mute row for (email, scope).
 	// Idempotent for row existence: calling it again for an already-muted
 	// address refreshes muted_at and replaces unmute_token if the token changes.

…rations/000078_muted_recipients.down.sql …rations/000091_muted_recipients.down.sqlinternal/database/postgres/migrations/000078_muted_recipients.down.sql renamed to internal/database/postgres/migrations/000091_muted_recipients.down.sql internal/database/postgres/migrations/000078_muted_recipients.down.sql renamed to internal/database/postgres/migrations/000091_muted_recipients.down.sql

@@ -181,13 +181,13 @@ func TestSendPurchaseApprovalRequest_WithCC_SuppressesListUnsubscribe(t *testing
 
 func TestBuildUnsubscribeURL_EmptyBaseURL_ReturnsEmpty(t *testing.T) {
 	s := &Sender{}
-	u, _ := s.buildUnsubscribeURL("user@example.com", "purchase_approvals")
+	u := s.buildUnsubscribeURL("user@example.com", "purchase_approvals")
 	assert.Empty(t, u)
 }
 
 func TestBuildUnsubscribeURL_WithBaseURL_ContainsParams(t *testing.T) {
 	s := &Sender{unsubscribeBaseURL: "https://dash.example.com"}
-	u, _ := s.buildUnsubscribeURL("user@example.com", "purchase_approvals")
+	u := s.buildUnsubscribeURL("user@example.com", "purchase_approvals")
 	assert.Contains(t, u, "email=user%40example.com")
 	assert.Contains(t, u, "scope=purchase_approvals")
 	assert.Contains(t, u, "token=")

…igrations/000078_muted_recipients.up.sql …igrations/000091_muted_recipients.up.sqlinternal/database/postgres/migrations/000078_muted_recipients.up.sql renamed to internal/database/postgres/migrations/000091_muted_recipients.up.sql internal/database/postgres/migrations/000078_muted_recipients.up.sql renamed to internal/database/postgres/migrations/000091_muted_recipients.up.sql

@@ -142,9 +142,9 @@ func muteKey() []byte {
 }
 
 // buildUnsubscribeURL constructs the one-click unsubscribe URL for the given
-// (email, scope) pair. Returns ("", "") when unsubscribeBaseURL is empty.
-func (s *Sender) buildUnsubscribeURL(email, scope string) (unsubURL, mailtoURL string) {
-	return unsubscribeURLFor(s.unsubscribeBaseURL, email, scope), ""
+// (email, scope) pair. Returns "" when unsubscribeBaseURL is empty.
+func (s *Sender) buildUnsubscribeURL(email, scope string) string {
+	return unsubscribeURLFor(s.unsubscribeBaseURL, email, scope)
 }
 
 // listUnsubscribeHeaders returns the List-Unsubscribe and List-Unsubscribe-Post

internal/email/mute_test.go

@@ -248,7 +248,7 @@ func (s *SMTPSender) buildSMTPMessageMultipartWithHeaders(toEmail string, cc []s
 	if len(cc) > 0 {
 		headers += fmt.Sprintf("Cc: %s\r\n", strings.Join(cc, ", "))
 	}
-	headers += fmt.Sprintf("Subject: %s\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=\"%s\"\r\n", subject, boundary)
+	headers += fmt.Sprintf("Subject: %s\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=%q\r\n", subject, boundary)
 	headers += extraHeaders
 	headers += "\r\n"
 

internal/email/sender.go

@@ -672,30 +672,6 @@ const purchaseApprovalRequestHTMLTemplate = `<!DOCTYPE html>
 </td></tr></table>
 </body></html>`
 
-// sendPurchaseApprovalRequestVia composes the plain-text + HTML approval-request
-// bodies and ships them through s.SendToEmailWithCCMultipart. HTML render
-// failures are non-fatal and degrade to single-part text so a template bug
-// never drops the approval email. Shared by Sender and SMTPSender — see
-// issue #287 / PR #298 dedup follow-up.
-func sendPurchaseApprovalRequestVia(ctx context.Context, s SenderInterface, recipient, subject string, data NotificationData) error {
-	textBody, err := RenderPurchaseApprovalRequestEmail(data)
-	if err != nil {
-		return fmt.Errorf("failed to render purchase approval request email (text): %w", err)
-	}
-	// HTML render failure is non-fatal: degrade to single-part text.
-	// SendToEmailWithCCMultipart already handles htmlBody=="" by delegating
-	// to the single-part path on each transport.
-	htmlBody, htmlErr := RenderPurchaseApprovalRequestEmailHTML(data)
-	if htmlErr != nil {
-		// Surface the render failure for production diagnosis. We deliberately
-		// don't return — text-only delivery is the safer fallback than dropping
-		// the approval email entirely.
-		logging.Warnf("email: HTML approval-request render failed, falling back to text-only: %v", htmlErr)
-		htmlBody = ""
-	}
-	return s.SendToEmailWithCCMultipart(ctx, recipient, data.CCEmails, subject, textBody, htmlBody)
-}
-
 // sendMultipartVia is the generic dual-render send helper used by the
 // invite / password-reset / welcome flows. The two render closures are
 // invoked back-to-back; an HTML render failure is non-fatal and degrades