fix: resolve review findings and refresh PR #1509 against main

changelog.d/114-open-map-overlays.md

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+- Add Sea Marks (OpenSeaMap) and Ski Pistes (OpenSnowMap) as two raster
+  overlay layers under Infrastructure. They drape on the globe stacks and on
+  Google 3D, and share links keep each one (Tom-Neverwinter, #114).

changelog.d/1308-overpass-admission-review-fixes.md

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+- Keep Overpass-backed layers working behind a reverse proxy: `/api/overpass`
+  now uses the keyless same-site gate, admits forwarding headers and still
+  refuses cross-site requests. Direct loopback requests keep their own
+  admission window; proxied requests, including those a local reverse proxy
+  relays over loopback, are admitted as remote traffic keyed by their socket,
+  and IPv6 peers are keyed by /64, so neither LAN peers nor proxied users can
+  exhaust the owner's admission. The upstream budget stays shared, so an owner
+  cache miss can still be rate-limited (asturksever, #1308).
+- Give the tracking arrival check a wall-clock budget per observed frame and
+  retry only an inconclusive timeout: a timeout keeps every angle it
+  measured, including a late frame's, and a wrong one fails without retry, so slow software-rendered
+  frames no longer fail the check and a real violation is never retried into a
+  pass (asturksever, #1308).

changelog.d/1435-military-positionless-rows.md

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+- Military aircraft that leave the adsb.lol feed fade and are removed again.
+  The feed's routine position-less rows no longer mark every snapshot partial,
+  which kept vanished aircraft at full opacity for up to five minutes; those
+  rows keep only their own aircraft, and a likely-landed one still leaves on
+  the landed limit (Aditya, @Rohilalala, #1435).