Add description/documentation field for events (for non-technical teams without code access)

Describe the feature or enhancement

Is your feature request related to a problem? Please describe.

Teams that don't have access to the codebase (e.g. SEO, marketing, product) have no way to understand what a tracked event actually means, where it's triggered, or what its properties represent. Right now the Events page only shows the event name and a breakdown of properties (via the Properties tab), with no context. This forces non-technical teammates to constantly ask developers "what is this click event for?" / "where is this triggered?", which doesn't scale as the number of tracked events grows.

Describe the solution you'd like

Allow an optional description/documentation field to be attached to each event (and ideally to each event property), editable directly from the Umami UI — not just in code. For example:

• An editable "Description" field per event, visible on the Events page (e.g. as a tooltip or expandable row)
• Optionally: a short note per property explaining what it represents
• Optionally: a "Status" indicator (active/deprecated) so teams know if an event is still in use

This would let teams maintain their event dictionary/tracking plan directly inside Umami, as the single source of truth, instead of relying on separate docs (Notion, Sheets, etc.) that go out of sync with the actual implementation.

Describe alternatives you've considered

• Maintaining a separate document (Notion/Sheet) mapping event names to descriptions — works but requires manual syncing and isn't visible where the data actually lives, so it drifts out of date.
• Naming conventions for events (e.g. page_element_action) — helps but doesn't cover context like "why this exists" or "which page/component triggers it."

Additional context

This would be especially valuable for teams where the people reading analytics (SEO, growth, product) are not the people implementing tracking (engineering), which is a very common setup.