fix: minor review comments

Author: aprimakina

internal/tiger/cmd/db.go

@@ -145,12 +145,17 @@ from your configuration. This command will launch an interactive psql session
 with the appropriate connection parameters.
 
 Authentication is handled automatically using:
-1. Stored password (keyring, ~/.pgpass, or none based on --password-storage setting)  
+1. Stored password (keyring, ~/.pgpass, or none based on --password-storage setting)
 2. PGPASSWORD environment variable
 3. If authentication fails, offers interactive options:
    - Enter password manually (will be saved for future use)
    - Reset password (update or generates a new password via the API)
 
+Use --read-only to open the psql session in Tiger Cloud's immutable read-only
+mode (writes and DDL are rejected by the server). The global read_only config
+option (or TIGER_READ_ONLY=true) also forces this behavior, so sessions started
+while read-only mode is on are always read-only.
+
 Examples:
   # Connect to default service
   tiger db connect

internal/tiger/common/errors.go

@@ -13,7 +13,7 @@ var ErrReadOnly = errors.New("this operation is not allowed in read-only mode")
 // CheckReadOnly returns ErrReadOnly if read-only mode is enabled. Callers
 // should invoke this before any destructive API call.
 func CheckReadOnly(cfg *config.Config) error {
-	if cfg != nil && cfg.ReadOnly {
+	if cfg.ReadOnly {
 		return ErrReadOnly
 	}
 	return nil

internal/tiger/common/errors_test.go

@@ -14,7 +14,6 @@ func TestCheckReadOnly(t *testing.T) {
 		cfg     *config.Config
 		wantErr error
 	}{
-		{name: "nil cfg allows writes", cfg: nil, wantErr: nil},
 		{name: "read-only off allows writes", cfg: &config.Config{ReadOnly: false}, wantErr: nil},
 		{name: "read-only on blocks writes", cfg: &config.Config{ReadOnly: true}, wantErr: ErrReadOnly},
 	}