fix: collision-aware !path hop resolution

[sg]

What changed

Rewrote !path path-hop resolution (commands/path.py) so a far repeater that merely shares a path-hash prefix can no longer supply a bogus distance.

• Repeater/room only: hops resolve against type IN (repeater, room) contacts (clients never repeat), shrinking the collision pool.
• Trust unique matches: a hash matching a single contact is used even if distant (it's unambiguous).
• Collision handling: when a hash matches >1 repeater, the hop is placed only if ≥2 candidates have a location and one is the clear nearest to a trusted anchor (the bot's own location, the sender, or an already-unambiguous neighbouring hop). A lone located candidate among a collision is left unlocated rather than guessed.

Why

During a tropospheric-ducting event, far repeaters (Louisiana/Dallas/Texarkana) were auto-added as contacts. One collided on its 2-byte path hash with a local repeater; the local (correct) hop had no geo, so the old "exactly one located contact" guard was silently defeated and !path reported the Louisiana location/distance. The fix detects the collision instead of trusting the only geo'd candidate.

Notes

• Considered (and rejected for now) max-distance and no-geo contact filters: the bot can't stop the radio's auto-add (only evict/skip post-hoc), and rejecting no-geo repeaters would have deleted the correct local hop, leaving the impostor to win. This resolver fix needs no contact-table changes and adds no magic distance threshold.
• Setting the bot's own location on the radio (self_info.adv_lat/lon) improves disambiguation.
• Tests: tests/test_path_resolve.py — impostor-collision → unlocated, two-geo collision → nearest-to-bot, unique far hop trusted, client excluded, geoless unique → unlocated, sender-as-anchor fallback.

Breaking changes

None. Pure accuracy fix; output format unchanged.