fix(greenplum): drop ctid from table-data SELECT and friendly-fail PK-less edits

Browsing any GP table threw "column ctid does not exist" because the
table-viewer's pagination query unconditionally appended `ctid::text`
to the SELECT. AO and AOCO tables (the dominant storage in GP)
genuinely have no ctid, and even on heap tables the value isn't
reliable across segments — so editing by ctid would be wrong even when
the column exists.

- get_table_data: skip the ctid column entirely on Greenplum (`SELECT *`
  instead of `SELECT *, ctid::text`); ctids field stays as an empty Vec.
- update_row / delete_rows: when the table has no PK on a GP connection,
  return an actionable error instead of falling through to the ctid
  path. Tells the user to add a PK or use raw SQL.

Vanilla Postgres behavior is unchanged.

src-tauri/src/commands/data.rs

@@ -136,9 +136,19 @@ pub async fn get_table_data(
 
     let offset = (page.saturating_sub(1)) * page_size;
 
+    // Greenplum AO / AOCO tables don't expose `ctid` and even on heap tables
+    // it isn't a reliable per-row identifier across segments — so on GP we
+    // skip the ctid column entirely. Edits without a PK will be rejected by
+    // update_row/delete_rows below with a friendly error.
+    let include_ctid = !matches!(flavor, DbFlavor::Greenplum);
+    let select_clause = if include_ctid {
+        "*, ctid::text"
+    } else {
+        "*"
+    };
     let data_sql = format!(
-        "SELECT *, ctid::text FROM {}{}{} LIMIT {} OFFSET {}",
-        qualified, where_clause, order_clause, page_size, offset
+        "SELECT {} FROM {}{}{} LIMIT {} OFFSET {}",
+        select_clause, qualified, where_clause, order_clause, page_size, offset
     );
     let count_sql = format!("SELECT COUNT(*) FROM {}{}", qualified, where_clause);
 
@@ -248,6 +258,13 @@ pub async fn update_row(
     let set_clause = format!("{} = $1", escape_ident(&column));
 
     if pk_columns.is_empty() {
+        if matches!(state.get_flavor(&connection_id).await, DbFlavor::Greenplum) {
+            return Err(TuskError::Custom(
+                "Greenplum doesn't expose a stable ctid (AO/AOCO tables have none, \
+                 heap-table ctid isn't unique across segments). Inline edit requires \
+                 a primary key — add one or use a SQL UPDATE.".into(),
+            ));
+        }
         // Fallback: use ctid for row identification
         let ctid_val = ctid.ok_or_else(|| {
             TuskError::Custom("Cannot update: no primary key and no ctid provided".into())
@@ -354,6 +371,13 @@ pub async fn delete_rows(
     let mut tx = pool.begin().await.map_err(TuskError::Database)?;
 
     if pk_columns.is_empty() {
+        if matches!(state.get_flavor(&connection_id).await, DbFlavor::Greenplum) {
+            return Err(TuskError::Custom(
+                "Greenplum doesn't expose a stable ctid (AO/AOCO tables have none, \
+                 heap-table ctid isn't unique across segments). Inline delete requires \
+                 a primary key — add one or use a SQL DELETE.".into(),
+            ));
+        }
         // Fallback: use ctids for row identification
         let ctid_list = ctids.ok_or_else(|| {
             TuskError::Custom("Cannot delete: no primary key and no ctids provided".into())