Add Cloudflare email and collaboration workflows

apps/server/internal/email/postmark.go

@@ -36,16 +36,21 @@ func NewPostmarkSender(serverToken, from, apiURL string, logger *slog.Logger) *P
 		serverToken: serverToken,
 		apiURL:      strings.TrimRight(apiURL, "/"),
 		from:        from,
-		client:      &http.Client{Timeout: postmarkTimeout},
-		logger:      logger,
+		client: &http.Client{
+			Timeout: postmarkTimeout,
+			CheckRedirect: func(req *http.Request, via []*http.Request) error {
+				return http.ErrUseLastResponse
+			},
+		},
+		logger: logger,
 	}
 }
 
 type postmarkRequest struct {
-	From     string `json:"From"`
-	To       string `json:"To"`
-	Subject  string `json:"Subject"`
-	TextBody string `json:"TextBody"`
+	From     string           `json:"From"`
+	To       string           `json:"To"`
+	Subject  string           `json:"Subject"`
+	TextBody string           `json:"TextBody"`
 	Headers  []postmarkHeader `json:"Headers,omitempty"`
 }
 
@@ -66,13 +71,13 @@ type postmarkResponse struct {
 // send if they need different reply-to addresses.
 func (p *PostmarkSender) Send(ctx context.Context, to []string, subject, body string) error {
 	if p.serverToken == "" {
-		return fmt.Errorf("postmark server token not configured")
+		return &PermanentError{Cause: fmt.Errorf("postmark server token not configured")}
 	}
 	if p.from == "" {
-		return fmt.Errorf("postmark from address not configured")
+		return &PermanentError{Cause: fmt.Errorf("postmark from address not configured")}
 	}
 	if len(to) == 0 {
-		return fmt.Errorf("postmark send requires at least one recipient")
+		return &PermanentError{Cause: fmt.Errorf("postmark send requires at least one recipient")}
 	}
 
 	payload := postmarkRequest{
@@ -96,7 +101,7 @@ func (p *PostmarkSender) Send(ctx context.Context, to []string, subject, body st
 
 	resp, err := p.client.Do(req)
 	if err != nil {
-		return fmt.Errorf("postmark request: %w", err)
+		return &TemporaryError{Cause: fmt.Errorf("postmark request: %w", err)}
 	}
 	defer resp.Body.Close()
 
@@ -107,7 +112,7 @@ func (p *PostmarkSender) Send(ctx context.Context, to []string, subject, body st
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return fmt.Errorf("postmark rejected: status=%d body=%s", resp.StatusCode, truncate(string(respBytes)))
+		return &PermanentError{Cause: fmt.Errorf("postmark rejected: status=%d body=%s", resp.StatusCode, truncate(string(respBytes)))}
 	}
 
 	var parsed postmarkResponse
@@ -117,7 +122,7 @@ func (p *PostmarkSender) Send(ctx context.Context, to []string, subject, body st
 	if parsed.ErrorCode != 0 {
 		// Postmark distinguishes "inactive recipient" (406) and other errors. Treat
 		// 406 as non-retryable; others bubble up as generic failures.
-		return fmt.Errorf("postmark error code=%d: %s", parsed.ErrorCode, parsed.Message)
+		return &PermanentError{Cause: fmt.Errorf("postmark error code=%d: %s", parsed.ErrorCode, parsed.Message)}
 	}
 
 	p.logger.Info("postmark email sent", "to", parsed.To, "subject", subject)
@@ -139,3 +144,11 @@ type TemporaryError struct {
 
 func (t *TemporaryError) Error() string { return t.Cause.Error() }
 func (t *TemporaryError) Unwrap() error { return t.Cause }
+
+// PermanentError marks a provider rejection that cannot succeed on retry.
+type PermanentError struct {
+	Cause error
+}
+
+func (p *PermanentError) Error() string { return p.Cause.Error() }
+func (p *PermanentError) Unwrap() error { return p.Cause }