Adaptive cache docs

[tillkruss]

• Add slot_cache_expiry description
• Review adaptive.md

[Copilot]

Pull Request Overview

Updates documentation to introduce adaptive caching, support Valkey alongside Redis, and prepare for a new slot cache expiry setting.

• Adds an adaptive caching guide.
• Updates menus and API docs to reference Valkey.
• Inserts placeholder for slot_cache_expiry in configuration.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
docs/1.x/index.md	Added Eviction and Ratios sections; reordered menu entries
docs/1.x/connections.md	Expanded Redis connection notes to include Valkey
docs/1.x/configuration.md	Updated invalidation endpoint note; added placeholder for expiry
docs/1.x/api.md	Adjusted metadata bullets for Redis/Valkey commands
docs/1.x/adaptive.md	New guide for adaptive caching setup

Comments suppressed due to low confidence (4)

docs/1.x/index.md:12

• The Ratios link currently points to /docs/1.x/events; it should target the correct ratios page (e.g., /docs/1.x/ratios).

  - [Ratios](/docs/1.x/events)

docs/1.x/index.md:14

• There are two Tables entries in this section; consider removing the duplicate to keep the menu concise.

  - [Tables](/docs/1.x/tables)

docs/1.x/configuration.md:51

• This entry has a placeholder (???); please provide a clear description of what slot_cache_expiry controls and its default behavior.

| `relay.cluster.slot_cache_expiry` |                  | ??? |

docs/1.x/api.md:26

• The RedisCommand bullet was removed when adding ValkeyCommand; you may want to retain both bullets to document the distinction between Redis and Valkey commands.

- `ValkeyCommand` indicates the method represents a [command](https://valkey.io/commands/)