fix: rewarp fly-back stuck recovery and precise landing

[nnasko]

Summary

• Fly rewarp now targets the actual start point (one block above the floor) so the 3D pathfinder routes under and around farm roofs and walls, instead of flying to a hard-coded Y=87 and stranding on top of structures
• FlyExecutor gains real stall detection (net distance-to-goal progress, not just per-tick movement), a FAILED state that propagates instead of hanging navigation, active braking during deceleration to stop sprint-momentum overshoots, resume-if-short corrections, and roof-aware vertical obstacle handling
• RewarpManager recovery chain: bounded retries with an alternating unstuck nudge, a navigation wall-clock timeout (the old wait loop could hang forever), a plot-TP/warp-garden fallback, and a safe macro stop if everything fails
• Arrival is now exact: the drop is only taken when the column below actually ends at start level, otherwise it aims at the start block centre and etherwarps onto it (same mechanics as the etherwarp pathfinder, with sneak priming and pre-click aim verification); landings are verified in XZ and Y with an etherwarp correction for wall-top misses
• Roof-climb AOTV in the pest destroyer levels the camera before moving toward pests
• Debug logging across the whole rewarp pipeline (attempts, results, distances, dy) behind Show Debug

Testing

• Verified in-game on a roofed farm: fly-back routes under the roof, brakes without overshooting, and lands on the exact start block; wall-top landings are corrected via etherwarp
• Recovery chain exercised in-game (stalled attempts, TP fallback, re-fly) via debug logs