v1.3.1 — URLs without a scheme now work

ROMarr v1.3.1 — a URL typed without a scheme now works.

Peer URL scheme probing (#59). The live failure: a friend's public URL stored as romarr.ant1695.fyi made every Friends-page call die with MissingSchema before anything was sent — "could not reach" for what was really a missing https://.

• New url_candidates() is the one rule for every URL a human typed: an explicit http:///https:// is honoured exactly; a scheme-less address is tried https first, then http; junk is refused with a message that says what to type.
• _call_friend probes candidates in order and keeps the first that answers — an answered 401/500 ends the probe (a refusal or sick server is not "unreachable"); only connection failures fall through to the next scheme.
• Normalized at birth too, so scheme-less URLs stop being stored: Federation.url, add_romm, accept_peer, the live public_url refresh, and the RomM friend client at use (legacy rows normalized defensively on read).

16 new tests including the reported bug verbatim and probe-order assertions. Full suite: 2241 passed, 3 skipped.