feat: add EndPoint.resolveAll() for multi-address DNS expansion (DRIVER-201) — Part 2/2

[nikagra]

Problem

`EndPoint.resolve()` returns a single `SocketAddress`. When a hostname maps to multiple IPs, the driver can only try the first one at the connection layer. If that IP is unreachable the driver fails with `AllNodesFailedException` even though other IPs are available.

Fixes DRIVER-201 at the general connection layer.

Note: This is part 2 of 2. Part 1 (#889) fixes the initial contact endpoints by expanding hostnames in the load-balancing query plan. This PR fixes the underlying `EndPoint` API and `ChannelFactory` so that any connection attempt — pool connections, reconnections, cloud SNI — benefits from multi-address fallback.

Changes

`EndPoint` interface

• `resolve()` is now `@Deprecated`.
• New `resolveAll()` default method returns `SocketAddress[]`. The default implementation wraps `resolve()` for backward compatibility with third-party implementations.

`DefaultEndPoint`

• Overrides `resolveAll()`: for unresolved addresses calls `InetAddress.getAllByName()` and returns one `InetSocketAddress` per IP. Falls back to a single-element array (the unresolved address) if DNS fails, so the connect attempt surfaces a descriptive error.

`SniEndPoint`

• Overrides `resolveAll()`: re-resolves the proxy hostname on each call, sorts all A-records by IP, and returns one `InetSocketAddress` per record — enabling the driver to try each proxy IP in sequence.

`ClientRoutesEndPoint`

• Overrides `resolveAll()`: wraps the single topology-monitor-resolved address in a one-element array (single-address by design).

`ChannelFactory`

• `connect()` now calls `endPoint.resolveAll()` instead of `endPoint.resolve()`.
• New `tryNextCandidate()` iterates through the returned array; on per-address failure it logs and tries the next; only fails the overall `resultFuture` when all candidates are exhausted.
• New `connectToAddress()` scopes protocol-version negotiation (downgrade retries) to a single address, which is semantically correct.

Tests

• `DefaultEndPointTest`: 3 new cases — already-resolved passthrough, unresolved hostname expansion, unresolvable hostname fallback.
• `SniEndPointTest`: new class covering `resolveAll()` happy path, unresolvable host exception, and `resolve()` sanity check.
• All 13 existing `ChannelFactory` tests pass unchanged (`LocalEndPoint` uses the default single-element `resolveAll()` via the interface default).