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/stores/app-store.ts

@@ -1,5 +1,5 @@
 import { create } from "zustand";
-import type { ConnectionConfig, Tab } from "@/types";
+import type { ConnectionConfig, DbFlavor, Tab } from "@/types";
 
 interface AppState {
   connections: ConnectionConfig[];
@@ -7,6 +7,7 @@ interface AppState {
   currentDatabase: string | null;
   connectedIds: Set<string>;
   readOnlyMap: Record<string, boolean>;
+  dbFlavors: Record<string, DbFlavor>;
   tabs: Tab[];
   activeTabId: string | null;
   sidebarWidth: number;
@@ -18,6 +19,7 @@ interface AppState {
   addConnectedId: (id: string) => void;
   removeConnectedId: (id: string) => void;
   setReadOnly: (connectionId: string, readOnly: boolean) => void;
+  setDbFlavor: (connectionId: string, flavor: DbFlavor) => void;
   setPgVersion: (version: string | null) => void;
 
   addTab: (tab: Tab) => void;
@@ -33,6 +35,7 @@ export const useAppStore = create<AppState>((set) => ({
   currentDatabase: null,
   connectedIds: new Set(),
   readOnlyMap: {},
+  dbFlavors: {},
   tabs: [],
   activeTabId: null,
   sidebarWidth: 260,
@@ -50,13 +53,22 @@ export const useAppStore = create<AppState>((set) => ({
     set((state) => {
       const next = new Set(state.connectedIds);
       next.delete(id);
-      const { [id]: _, ...restRo } = state.readOnlyMap;
-      return { connectedIds: next, readOnlyMap: restRo };
+      const restRo = Object.fromEntries(
+        Object.entries(state.readOnlyMap).filter(([k]) => k !== id)
+      );
+      const restFlavors = Object.fromEntries(
+        Object.entries(state.dbFlavors).filter(([k]) => k !== id)
+      );
+      return { connectedIds: next, readOnlyMap: restRo, dbFlavors: restFlavors };
     }),
   setReadOnly: (connectionId, readOnly) =>
     set((state) => ({
       readOnlyMap: { ...state.readOnlyMap, [connectionId]: readOnly },
     })),
+  setDbFlavor: (connectionId, flavor) =>
+    set((state) => ({
+      dbFlavors: { ...state.dbFlavors, [connectionId]: flavor },
+    })),
   setPgVersion: (version) => set({ pgVersion: version }),
 
   addTab: (tab) =>