add dynamic profile update, connection helper, file download metadata

- replace UserSetColor/UserSetPronouns with single UserUpdateProfile that dynamically builds one UPDATE query from UserProfileUpdateList
- add getConnectionWithResponseOnFail helper to deduplicate connection ID parsing and validation across handlers
- rename file.go to attachmentFile.go and update handler names
- GetDownloadUrlAndMetadata now fetches object metadata via StatObject and returns it alongside the presigned URL
- file download endpoint returns JSON with url and originalName
- add description field to user and DB schema
- remove unused ConnectionState variants (GroupFellow, GroupFriend)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/postgresql/postgresql.go

@@ -3,6 +3,7 @@ package postgresql
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"go-socket/packages/cache"
@@ -33,6 +34,9 @@ func Init(ctx context.Context) {
 		    name TEXT UNIQUE NOT NULL,
 		    pass_hash TEXT NOT NULL,
 		    pronouns TEXT DEFAULT NULL,
+			description TEXT DEFAULT NULL,
+			avatar TEXT DEFAULT NULL,
+			profileBg TEXT DEFAULT NULL,
 		    rgba BIGINT NOT NULL DEFAULT 0 CHECK (rgba BETWEEN 0 AND 4294967295),
 			created_at TIMESTAMP NOT NULL DEFAULT NOW()
 		)
@@ -108,17 +112,35 @@ func UserGetById(ctx context.Context, user *types.User) error {
 	return err
 }
 
-func UserSetColor(ctx context.Context, user *types.User) error {
-	_, err := dbConn.Exec(ctx, `
-		UPDATE users SET rgba = $1 WHERE id = $2
-	`, convertions.RgbaToUint32(user.Color), user.Id)
-	return err
-}
+func UserUpdateProfile(ctx context.Context, user *types.User, updateList types.UserProfileUpdateList) error {
+	setClauses := make([]string, 0, 3)
+	args := make([]any, 0, 4)
+	argIdx := 1
 
-func UserSetPronouns(ctx context.Context, user *types.User) error {
-	_, err := dbConn.Exec(ctx, `
-		UPDATE users SET pronouns = $1 WHERE id = $2
-	`, user.Pronouns, user.Id)
+	if updateList.Pronouns {
+		setClauses = append(setClauses, fmt.Sprintf("pronouns = $%d", argIdx))
+		args = append(args, user.Pronouns)
+		argIdx++
+	}
+	if updateList.Description {
+		setClauses = append(setClauses, fmt.Sprintf("description = $%d", argIdx))
+		args = append(args, user.Description)
+		argIdx++
+	}
+	if updateList.Color {
+		setClauses = append(setClauses, fmt.Sprintf("rgba = $%d", argIdx))
+		args = append(args, convertions.RgbaToUint32(user.Color))
+		argIdx++
+	}
+
+	if len(setClauses) == 0 {
+		return nil
+	}
+
+	query := "UPDATE users SET " + strings.Join(setClauses, ", ") + fmt.Sprintf(" WHERE id = $%d", argIdx)
+	args = append(args, user.Id)
+
+	_, err := dbConn.Exec(ctx, query, args...)
 	return err
 }