Mini-apps

**What the feature is (as Title)**
Mini-apps: custom apps built for your data

**Value proposition**
Teams can build small tools inside Kibana using code, platform components and pre-built actions. Dashboards show the problem; mini-apps add the buttons and forms to fix it.

**Expected outcome**
Lower time to resolution from less context-switching and less engineering time spent on bespoke internal tooling.

**Optional: Key user stories / use cases**

This is a high-level roadmap proposal for mini-apps inside Kibana. No files, tests, entry points, implementation scope, or acceptance criteria are provided, so first clarify the intended capability and define what completion looks like before locating code.

Written by the indexing model from the issue text.