Extract climb detection into a dedicated climb package

Move climb detection, slope, and Cotacol scoring out of ride into a new
climb package that operates on a geometry-only Route (distances, elevations,
coords). Ride embeds climb.Route and keeps its timing and telemetry columns.

- climb.Detect returns []DetectedClimb (Climb + ride-absolute Start).
- Climb owns its sliced geometry; indices are local, with Start reported at
  the detection boundary for absolute position.
- Detected bounds use core.Interval; freeRegions claim suppression fixed.
- ride no longer builds slices: ClimbFromDist/ClimbFromIndexes/climbFrom and
  ride.Climb/Interval/Range are removed; rideanalysis, mountain_pass MatchClimb,
  and web views are rewired to climb types.
- New internal/routetest builds climb.Route from the ride DSL; ridetest reuses
  it and adds timestamps and telemetry.
- Tests moved to climb (synthetic detection and difficulty) and kept in ride
  for GPX-example integration; ride.comparison detection coverage retained.
- mountain_pass.nearestCrossing now reuses geo.Nearest.

1 files changed, 15 insertions, 18 deletions

diff --git a/mountain_pass/detection.go b/mountain_pass/detection.go
index 40281f3..79e55e4 100644
--- a/mountain_pass/detection.go
+++ b/mountain_pass/detection.go
@@ -5,7 +5,8 @@ import (
 	"math"
 
 	"github.com/jftuga/geodist"
-	"github.com/martinlehoux/biking_home/ride"
+	"github.com/martinlehoux/biking_home/climb"
+	"github.com/martinlehoux/biking_home/geo"
 )
 
 // MountainPass is a pass extracted from OpenStreetMap: a node tagged
@@ -112,9 +113,9 @@ func DetectCrossings(coords []geodist.Coord, distances, elevations []float64, pa
 // MatchClimb returns the pass whose coordinates lie within radiusM of the
 // climb's highest point and whose elevation is within elevationToleranceM of
 // that point's elevation, nearest first. Found is false when no pass matches.
-func MatchClimb(climb ride.Climb, passes []MountainPass, radiusM, elevationToleranceM float64) (MountainPass, bool) {
-	topCoord := climb.TopCoord()
-	topElevation := climb.TopElevationM()
+func MatchClimb(segment climb.Climb, passes []MountainPass, radiusM, elevationToleranceM float64) (MountainPass, bool) {
+	topIndex, topElevation := segment.Top()
+	topCoord := segment.Coords[topIndex]
 	var best MountainPass
 	bestDistanceM := radiusM
 	found := false
@@ -139,21 +140,17 @@ func MatchClimb(climb ride.Climb, passes []MountainPass, radiusM, elevationToler
 }
 
 func nearestCrossing(coords []geodist.Coord, distances, elevations []float64, mountainPass MountainPass) (Crossing, bool) {
-	best := Crossing{Pass: mountainPass, DistanceToM: 1e18}
-	for i := range coords {
-		distanceKm, _ := geodist.HaversineDistance(coords[i], *mountainPass.Coord)
-		distanceM := distanceKm * 1000
-		if distanceM < best.DistanceToM {
-			best.DistanceToM = distanceM
-			best.RideDistanceM = distances[i]
-			best.RideElevation = elevations[i]
-			best.ElevationDiff = absFloat64(elevations[i] - float64(mountainPass.Elevation))
-		}
-	}
-	if best.DistanceToM > 1e17 {
-		return best, false
+	index, distanceM := geo.Nearest(coords, *mountainPass.Coord)
+	if math.IsInf(distanceM, 1) {
+		return Crossing{Pass: mountainPass}, false
 	}
-	return best, true
+	return Crossing{
+		Pass:          mountainPass,
+		DistanceToM:   distanceM,
+		RideDistanceM: distances[index],
+		RideElevation: elevations[index],
+		ElevationDiff: absFloat64(elevations[index] - float64(mountainPass.Elevation)),
+	}, true
 }
 
 func absFloat64(value float64) float64 {