feat(article): expose auto_publish_platforms derived from publish accounts

Replace the freeform `platforms` field on articles/tasks (parsed out of
wizard_state/input_params JSON) with `auto_publish_platforms`, resolved
by joining schedule publish accounts to platform_accounts. The migration
strips the legacy keys from existing rows so the new field is the single
source of truth.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/app/publish_platforms.go

@@ -1,9 +1,12 @@
 package app
 
 import (
+	"context"
 	"encoding/json"
 	"strconv"
 	"strings"
+
+	"github.com/jackc/pgx/v5"
 )
 
 func normalizePlatformIDs(platformIDs []string) []string {
@@ -31,52 +34,79 @@ func normalizePlatformIDs(platformIDs []string) []string {
 	return normalized
 }
 
-func parsePlatformIDs(value string) []string {
-	if strings.TrimSpace(value) == "" {
-		return nil
-	}
-	return normalizePlatformIDs(strings.Split(value, ","))
+type scheduleAutoPublishPlatformQuerier interface {
+	Query(context.Context, string, ...interface{}) (pgx.Rows, error)
 }
 
-func serializePlatformIDs(platformIDs []string) string {
-	normalized := normalizePlatformIDs(platformIDs)
-	if len(normalized) == 0 {
-		return ""
-	}
-	return strings.Join(normalized, ",")
-}
-
-func resolveArticlePlatforms(wizardStateJSON, inputParamsJSON []byte) []string {
-	if platforms := extractPlatformsFromJSONPayload(wizardStateJSON); len(platforms) > 0 {
-		return platforms
-	}
-	if platforms := extractPlatformsFromJSONPayload(inputParamsJSON); len(platforms) > 0 {
-		return platforms
-	}
-	return []string{}
-}
-
-func extractPlatformsFromJSONPayload(raw []byte) []string {
-	if len(raw) == 0 {
-		return nil
+func loadScheduleAutoPublishPlatforms(
+	ctx context.Context,
+	db scheduleAutoPublishPlatformQuerier,
+	tenantID int64,
+	inputParamsJSON []byte,
+) ([]string, error) {
+	if db == nil || tenantID <= 0 || len(inputParamsJSON) == 0 {
+		return []string{}, nil
 	}
 
 	var payload map[string]interface{}
-	if err := json.Unmarshal(raw, &payload); err != nil {
-		return nil
+	if err := json.Unmarshal(inputParamsJSON, &payload); err != nil {
+		return []string{}, nil
+	}
+	if !extractBool(payload, "schedule_auto_publish") {
+		return []string{}, nil
 	}
 
-	if platforms := normalizePlatformsFromValue(payload["platforms"]); len(platforms) > 0 {
-		return platforms
-	}
-	if platforms := normalizePlatformsFromValue(payload["target_platforms"]); len(platforms) > 0 {
-		return platforms
+	accountIDs := normalizeSchedulePublishAccountIDs(extractStringList(payload["schedule_publish_account_ids"], 64))
+	if len(accountIDs) == 0 {
+		return []string{}, nil
 	}
 
-	if targetPlatform, ok := payload["target_platform"].(string); ok {
-		return parsePlatformIDs(targetPlatform)
+	return loadPublishAccountPlatformsByIDs(ctx, db, tenantID, accountIDs)
+}
+
+func loadPublishAccountPlatformsByIDs(
+	ctx context.Context,
+	db scheduleAutoPublishPlatformQuerier,
+	tenantID int64,
+	accountIDs []string,
+) ([]string, error) {
+	accountIDs = normalizeSchedulePublishAccountIDs(accountIDs)
+	if db == nil || tenantID <= 0 || len(accountIDs) == 0 {
+		return []string{}, nil
 	}
-	return nil
+
+	rows, err := db.Query(ctx, `
+		SELECT DISTINCT platform_id
+		FROM platform_accounts
+		WHERE tenant_id = $1
+		  AND desktop_id::text = ANY($2::text[])
+		  AND deleted_at IS NULL
+		ORDER BY platform_id
+	`, tenantID, accountIDs)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	platformIDs := make([]string, 0, len(accountIDs))
+	for rows.Next() {
+		var platformID string
+		if err := rows.Scan(&platformID); err != nil {
+			return nil, err
+		}
+		platformIDs = append(platformIDs, platformID)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return emptyStringSliceIfNil(normalizePlatformIDs(platformIDs)), nil
+}
+
+func emptyStringSliceIfNil(values []string) []string {
+	if values == nil {
+		return []string{}
+	}
+	return values
 }
 
 func resolveArticleCoverAssetURL(wizardStateJSON []byte) *string {
@@ -146,51 +176,21 @@ func extractInt64FromJSONPayload(raw []byte, key string) (int64, bool) {
 	}
 }
 
-func normalizePlatformsFromValue(raw interface{}) []string {
-	switch typed := raw.(type) {
-	case nil:
-		return nil
-	case string:
-		return parsePlatformIDs(typed)
-	case []string:
-		return normalizePlatformIDs(typed)
-	case []interface{}:
-		values := make([]string, 0, len(typed))
-		for _, item := range typed {
-			value, ok := item.(string)
-			if !ok {
-				continue
-			}
-			values = append(values, value)
-		}
-		return normalizePlatformIDs(values)
-	default:
-		return nil
-	}
-}
-
-func mergeArticleWizardState(raw []byte, title string, platforms []string, coverAssetURL *string, coverImageAssetID NullableInt64Input) ([]byte, error) {
+func mergeArticleWizardState(raw []byte, title string, coverAssetURL *string, coverImageAssetID NullableInt64Input) ([]byte, error) {
 	state := make(map[string]interface{})
 	if len(raw) > 0 {
 		_ = json.Unmarshal(raw, &state)
 	}
 
+	delete(state, "platforms")
+	delete(state, "target_platforms")
+	delete(state, "target_platform")
+
 	trimmedTitle := strings.TrimSpace(title)
 	if trimmedTitle != "" {
 		state["title"] = trimmedTitle
 	}
 
-	if platforms != nil {
-		normalized := normalizePlatformIDs(platforms)
-		if len(normalized) == 0 {
-			delete(state, "platforms")
-			delete(state, "target_platform")
-		} else {
-			state["platforms"] = normalized
-			state["target_platform"] = strings.Join(normalized, ",")
-		}
-	}
-
 	if coverAssetURL != nil {
 		trimmedCoverURL := strings.TrimSpace(*coverAssetURL)
 		if trimmedCoverURL == "" {