Saved filters: name a View filter and switch to it in one click #457

Use case

An operator sets up the map for a specific job and needs it back instantly, often under pressure:

• EOC / storm spotting: the Skywarn spotters list, weather stations, and anything heard within 30 min.
• Event volunteering: the MS150 volunteers list plus the event's objects (aid stations, sweep vehicles), with everyone else hidden.
• Checking the local network: RF direct only, digipeaters, heard within 2 h.

Today, F1.9 has one My filter and All. Station lists (F1.33, #328) cover who, but the rest of the filter (kinds, categories, heard within, reception, tags) has to be set up again by hand each time the job changes.

Proposal (outline, to be specced as F1.42)

1. Save filter as… in the Filter panel saves the current conditions under a name ("Storm spotting"). Station lists are included by reference, so editing a list updates every filter that uses it.

2. Saved filters belong to the profile (maintainer, 2026-10-27), as station lists do. On a gateway, whoever may change settings sets them up, and every viewer can use them, as fits an EOC where several people watch one gateway. Switching profile switches the set. Up to 20 per profile. My filter stays per viewer.

3. One-click switching: the map's filter chip becomes a menu with All, My filter and each saved filter. The chip names the filter in use ("Storm spotting · 42 of 2,140"). A keyboard shortcut cycles through them.

4. Using a saved filter doesn't change it. Adjusting conditions while one is in use shows "Storm spotting (changed)", with Save and Save as new. Rename, Delete and reorder are in Settings › Station lists, renamed Lists and filters.

5. Receiving: a saved filter in use that shows a station list joins the APRS-IS filter exactly as the list does (F1.33 behavior 9).

6. Plain text in and out, like lists. Copy filter gives a short readable text ("lists: Skywarn spotters; categories: weather; heard: 30 min") to paste into another profile or station.

7. Emergencies are always shown (F1.9 behavior 3).

8. An optional map view per filter (maintainer, 2026-10-27): each saved filter can also keep a map area and zoom ("the event area", "the county"), set with Use this map view when saving and cleared with Don't move the map. Switching to a filter with a view moves the map there; one without leaves the map where it is. Kept apart from saved layouts (F1.23), which arrange panels, not filters.