feat: allow Python and Typescript users to create Sessions (#2530)

## Summary
- Exposes `Session` in Python and Typescript so users can set the
`index_cache_size_bytes` and `metadata_cache_size_bytes`
* The `Session` is attached to the `Connection`, and thus shared across
all tables in that connection.
- Adds deprecation warnings for table-level cache configuration


🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude <noreply@anthropic.com>

nodejs/__test__/session.test.ts

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright The LanceDB Authors
+
+import * as tmp from "tmp";
+import { Session, connect } from "../lancedb";
+
+describe("Session", () => {
+  let tmpDir: tmp.DirResult;
+  beforeEach(() => {
+    tmpDir = tmp.dirSync({ unsafeCleanup: true });
+  });
+  afterEach(() => tmpDir.removeCallback());
+
+  it("should configure cache sizes and work with database operations", async () => {
+    // Create session with small cache limits for testing
+    const indexCacheSize = BigInt(1024 * 1024); // 1MB
+    const metadataCacheSize = BigInt(512 * 1024); // 512KB
+
+    const session = new Session(indexCacheSize, metadataCacheSize);
+
+    // Record initial cache state
+    const initialCacheSize = session.sizeBytes();
+    const initialCacheItems = session.approxNumItems();
+
+    // Test session works with database connection
+    const db = await connect({ uri: tmpDir.name, session: session });
+
+    // Create and use a table to exercise the session
+    const data = Array.from({ length: 100 }, (_, i) => ({
+      id: i,
+      text: `item ${i}`,
+    }));
+    const table = await db.createTable("test", data);
+    const results = await table.query().limit(5).toArray();
+
+    expect(results).toHaveLength(5);
+
+    // Verify cache usage increased after operations
+    const finalCacheSize = session.sizeBytes();
+    const finalCacheItems = session.approxNumItems();
+
+    expect(finalCacheSize).toBeGreaterThan(initialCacheSize); // Cache should have grown
+    expect(finalCacheItems).toBeGreaterThanOrEqual(initialCacheItems); // Items should not decrease
+    expect(initialCacheSize).toBeLessThan(indexCacheSize + metadataCacheSize); // Within limits
+  });
+});