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/management/AdminPanel.tsx

@@ -54,6 +54,7 @@ export function AdminPanel() {
             type: "roles",
             title: "Roles & Users",
             connectionId: activeConnectionId,
+            database: currentDatabase ?? undefined,
           };
           addTab(tab);
         }}
@@ -66,6 +67,7 @@ export function AdminPanel() {
             type: "sessions",
             title: "Active Sessions",
             connectionId: activeConnectionId,
+            database: currentDatabase ?? undefined,
           };
           addTab(tab);
         }}