Cut climb profile sections in the backend

The chart steps are computed in Go and shipped as finished sections, next to
the profile statistics the climb package already owns: climb.ProfileSections
cuts a Route at its widest bends under a ProfilePolicy, and
rideanalysis.MergeClimbProfile takes over the merge that lived in
web/climbs.go, so web only loads the attempt rides and maps the DTOs.

The payload carries sections instead of raw elevations, and the browser keeps
what needs the canvas: slope bands, labels, distance ticks and colours.
official-climb-profile-logic.ts and its tests are gone, replaced by
climb/profile_test.go and a page test reading the embedded profile JSON.

1 files changed, 21 insertions, 0 deletions

diff --git a/web/frontend/types.d.ts b/web/frontend/types.d.ts
index a933d7d..a97d07d 100644
--- a/web/frontend/types.d.ts
+++ b/web/frontend/types.d.ts
@@ -2,6 +2,25 @@ export type ProfileBand = "downhill" | "0-3" | "3-6" | "6-9" | "9-plus";
 export type BoundaryTarget = "start" | "end";
 export type BoundarySource = "profile" | "map";
 
+// ProfileSectionPayload is one step of a climb profile as the server cuts it.
+export interface ProfileSectionPayload {
+  startKm: number;
+  endKm: number;
+  startElevationM: number;
+  endElevationM: number;
+  slopePercent: number;
+}
+
+// OfficialProfileSection is that step tagged with the colour band its slope falls in.
+export interface OfficialProfileSection {
+  startDistanceKm: number;
+  endDistanceKm: number;
+  startElevation: number;
+  endElevation: number;
+  slopePercent: number;
+  band: ProfileBand;
+}
+
 export interface ProfilePoint {
   distanceKm: number;
   elevationM: number;
@@ -14,6 +33,7 @@ export interface RideProfilePoint extends ProfilePoint {
 }
 
 export interface RideProfileClimb {
+  index: number;
   startKm: number;
   endKm: number;
   topKm: number;
@@ -27,6 +47,7 @@ export interface RideProfileClimb {
   officialName?: string;
   startIndex: number;
   endIndex: number;
+  sections?: ProfileSectionPayload[];
 }
 
 export interface RideProfileCrossing {