fix(model): let loadLocationStables honour forceMinimum

[Ryanmello07]

loadLocationStables hardcoded forceMinimum=false on the read side, so a location whose every provider fails the minimums gate is invisible even to callers that explicitly bypass minimums. Location enumeration happens before provider selection, so force_minimum on find-providers2 cannot recover a location the listing never emitted — those providers can never be reached and never improve their standing.

The writer (UpdateClientScores -> exportClientScores, which loops for _, forceMinimum := range []bool{false, true}) already populates both key families, so this only chooses between them. No new data, no new keys.

Both existing callers — GetProviderLocations and FindProviderLocations — pass false explicitly, so user-facing location listing is byte-for-byte unchanged.

New test TestLoadLocationStablesHonoursForceMinimum: one connected+valid Public provider with no latency or speed samples (deterministically below the minimums); its country is absent under false and present under true.

🤖 Generated with Claude Code

https://claude.ai/code/session_01QtgqtCmKJRXdsQ5ktiqwkg

[Ryanmello07]

Superseded by #425, which consolidates this stack into a single branch rebased onto current main. The work is unchanged and included there — this PR's commits are in #425's history (or, where the chain rewrote them, their final form is). Closing to keep review in one place.