Add informSearchFailed method to update GPS power state handling

[thebentern]

No description provided.

[Copilot]

Pull request overview

This PR refines GPS search-cycle bookkeeping so the scheduler can distinguish between a successful fix and a search timeout, improving subsequent GPS power-state decisions.

Changes:

• Add GPSUpdateScheduling::informSearchFailed() to record the end of a search that timed out without updating the lock-time prediction.
• Update GPS::down() to call informGotLock() only when a valid location was obtained, otherwise call informSearchFailed().
• Minor comment updates to reflect the “lock or timeout” semantics of GPS::down().

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/gps/GPSUpdateScheduling.h	Declares the new informSearchFailed() API for timeout-ended search cycles.
src/gps/GPSUpdateScheduling.cpp	Implements informSearchFailed() to mark searchEndedMs without modifying the lock-time prediction.
src/gps/GPS.cpp	Routes GPS::down() scheduling updates through success vs timeout paths based on hasValidLocation.