feat: add limit option to useResponseCaching for entry eviction

[ascott18]

Summary

Adds a limit option to useResponseCaching() that constrains how many cached responses are stored per endpoint group. When limits are exceeded, the oldest entries are evicted first.

Configuration

caller.useResponseCaching({
  limit: {
    key: string,          // Custom group key (default: endpoint path without query params)
    maxEntries: number,   // Max cached entries per group
    maxBytes: number,     // Max total serialized size per group
  },
});

Implementation

• Group metadata is stored in the same Storage alongside cache entries, using a coalesce:group: key prefix
• Each group metadata entry tracks the cache key, timestamp, and serialized size of each member entry
• On cache write, stale references (entries removed by purgeStaleCacheEntries or other means) are cleaned up from group metadata
• The newest entry is never evicted, even if it alone exceeds maxBytes

Changes

• src/coalesce-vue/src/api-client.ts - Added limit to ResponseCachingConfiguration type, added enforceGroupLimits() helper, updated cache write path
• src/coalesce-vue/test/api-client.spec.ts - Tests for maxEntries, maxBytes, custom group keys, and stale reference cleanup
• docs/stacks/vue/layers/api-clients.md - Updated documentation with limit option details and example
• CHANGELOG.md - Added changelog entry

[Copilot]

Pull request overview

Adds an optional limit configuration to useResponseCaching() in coalesce-vue to cap cached responses per endpoint group (by entry count and/or total serialized size), evicting oldest entries first. This extends the existing client-side response cache behavior and documents the new configuration for framework consumers.

Changes:

• Extended ResponseCachingConfiguration with a limit option and implemented group metadata + eviction via enforceGroupLimits().
• Added test coverage for maxEntries, maxBytes, custom group keys, function-based keys, and stale-reference cleanup.
• Updated Vue API client docs and added a changelog entry describing the new option.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
src/coalesce-vue/src/api-client.ts	Adds limit configuration, persists group metadata in Storage, and enforces per-group eviction on cache writes.
src/coalesce-vue/test/api-client.spec.ts	Adds tests covering eviction behavior and group metadata handling.
docs/stacks/vue/layers/api-clients.md	Documents the new limit option and provides an example.
CHANGELOG.md	Notes the new limit option for useResponseCaching.

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