feat: add Greenplum 7 compatibility and AI SQL generation

Greenplum 7 (PG12-based) compatibility:
- Auto-detect GP via version() string, store DbFlavor per connection
- connect returns ConnectResult with version + flavor
- Fix pg_total_relation_size to use c.oid (universal, safer on both PG/GP)
- Branch is_identity column query for GP (lacks the column)
- Branch list_sessions wait_event fields for GP
- Exclude gp_toolkit schema in schema listing, completion, lookup, AI context
- Smart StatusBar version display: GP shows "GP 7.0.0 (PG 12.4)"
- Fix connection list spinner showing on all cards during connect

AI SQL generation (Ollama):
- Add AI settings, model selection, and generate_sql command
- Frontend AI panel with prompt input and SQL output

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

src/components/connections/ConnectionList.tsx

@@ -25,6 +25,7 @@ import {
 import type { ConnectionConfig } from "@/types";
 import { EnvironmentBadge } from "@/components/connections/EnvironmentBadge";
 import { ENVIRONMENTS } from "@/lib/environment";
+import { useState } from "react";
 
 interface Props {
   open: boolean;
@@ -39,8 +40,10 @@ export function ConnectionList({ open, onOpenChange, onEdit, onNew }: Props) {
   const connectMutation = useConnect();
   const disconnectMutation = useDisconnect();
   const { connectedIds, activeConnectionId } = useAppStore();
+  const [connectingId, setConnectingId] = useState<string | null>(null);
 
   const handleConnect = (conn: ConnectionConfig) => {
+    setConnectingId(conn.id);
     connectMutation.mutate(conn, {
       onSuccess: () => {
         toast.success(`Connected to ${conn.name}`);
@@ -49,6 +52,9 @@ export function ConnectionList({ open, onOpenChange, onEdit, onNew }: Props) {
       onError: (err) => {
         toast.error("Connection failed", { description: String(err) });
       },
+      onSettled: () => {
+        setConnectingId(null);
+      },
     });
   };
 
@@ -169,9 +175,9 @@ export function ConnectionList({ open, onOpenChange, onEdit, onNew }: Props) {
                                 variant="ghost"
                                 className="h-7 w-7"
                                 onClick={() => handleConnect(conn)}
-                                disabled={connectMutation.isPending}
+                                disabled={connectingId !== null}
                               >
-                                {connectMutation.isPending ? (
+                                {connectingId === conn.id ? (
                                   <Loader2 className="h-3.5 w-3.5 animate-spin" />
                                 ) : (
                                   <Plug className="h-3.5 w-3.5" />