fix: encode !path geojson.io URL with safe='' so slashes don't break the map

[sg]

Problem

!path sometimes produced a geojson.io map link that errored with "unterminated string in the json data" — but only for some paths.

Root cause

geojson.io's data-URL API expects encodeURIComponent(JSON.stringify(...)). path.py built the link with urllib.parse.quote(data), whose default safe="/" leaves forward slashes unescaped (unlike encodeURIComponent, which escapes /). So a hop whose node name contains / put a bare / inside the JSON payload in the #data= hash, and geojson.io's parser cut the JSON at that slash → "unterminated string." Only /-bearing names trip it, hence "some paths."

Ruled out: da.gd (stores targets intact to 10 KB+ in testing) and the JSON itself (valid, round-trips).

Fix

enc = urllib.parse.quote(data, safe="")   # was urllib.parse.quote(data)

safe="" matches encodeURIComponent, percent-encoding / (and everything else). Strictly more correct; over-encoding decodes identically, so working paths are unaffected.

Verification

For a path with a /-named hop: slash now encodes to %2F, the payload parses as valid JSON, and the full da.gd → geojson.io round-trip parses cleanly.