docs: document per-trip map settings (use_gpx, autoconnect) in README

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Vgmzx8VTTTmCskSpQtsLTr

README.md

@@ -149,6 +149,24 @@ Key design decisions that affect how pages render:
 
 Entries and stories opt into the highlights grid via `featured: true` in their frontmatter. The `active_trip` field stores a full page route (e.g. `/trips/italy-2026-demo`), not a bare slug.
 
+**Per-trip map settings** — configurable in Admin2 under the Trip tab:
+
+| Setting | Values | Default | Notes |
+|---|---|---|---|
+| `use_gpx` | Yes / No | Yes | Draws uploaded GPX files as route lines on the map |
+| `autoconnect` | off / on / manual / intelligent_gpx | on | Controls connector lines between location markers |
+
+Connect markers behaviour:
+
+| Value | Behaviour |
+|---|---|
+| `off` | No connector lines; `force_connect` on entries is also ignored |
+| `on` | Dashed connector between every entry in date order |
+| `manual` | No automatic lines; only entries with `force_connect: true` are linked |
+| `intelligent_gpx` | Suppresses the connector where a GPX track covers the route; `force_connect` overrides. Requires `use_gpx` enabled — falls back to `on` if GPX is off or no files are present |
+
+`use_gpx` and `autoconnect` are independent: you can show GPX tracks without connector lines or vice versa.
+
 ---
 
 ## Security