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, 17 insertions, 32 deletions

diff --git a/web/frontend/climb-profile.ts b/web/frontend/climb-profile.ts
index 6051ec1..d06d291 100644
--- a/web/frontend/climb-profile.ts
+++ b/web/frontend/climb-profile.ts
@@ -1,32 +1,21 @@
-import { drawOfficialSections, officialProfilePlot, resolveOfficialProfileColors } from "./official-climb-profile.js";
-import { officialProfileSections } from "./official-climb-profile-logic.js";
-import type { OfficialProfileSection } from "./official-climb-profile-logic.js";
-import type { ProfilePoint } from "./types.js";
+import {
+  drawOfficialSections,
+  officialProfilePlot,
+  officialProfileSections,
+  resolveOfficialProfileColors,
+} from "./official-climb-profile.js";
+import type { OfficialProfileSection, ProfileSectionPayload } from "./types.js";
 
 interface ClimbProfilePayload {
-  distanceKm: number;
-  elevations: number[];
+  sections: ProfileSectionPayload[];
 }
 
 interface ClimbProfileState {
   canvas: HTMLCanvasElement;
-  payload: ClimbProfilePayload;
   sections: OfficialProfileSection[];
   hoverOutput: HTMLOutputElement;
 }
 
-const climbProfilePoints = (payload: ClimbProfilePayload): ProfilePoint[] =>
-  payload.elevations.map((elevationM, index) => ({
-    distanceKm: (payload.distanceKm * index) / (payload.elevations.length - 1),
-    elevationM,
-  }));
-
-const climbProfileSections = (payload: ClimbProfilePayload): OfficialProfileSection[] => {
-  const points = climbProfilePoints(payload);
-  if (points.length < 2) return [];
-  return officialProfileSections(points, 0, points.length - 1);
-};
-
 const elevationAtDistance = (sections: OfficialProfileSection[], distanceKm: number): number | null => {
   for (const section of sections) {
     if (distanceKm >= section.startDistanceKm && distanceKm <= section.endDistanceKm) {
@@ -64,15 +53,13 @@ const drawHoverMarker = (state: ClimbProfileState, distanceKm: number): void =>
   state.hoverOutput.textContent = `${distanceKm.toFixed(2)} km · ${Math.round(elevation)} m`;
 };
 
-const clearHover = (state: ClimbProfileState): void => {
-  drawClimbProfile(state.canvas, state.payload, state.sections);
-  state.hoverOutput.textContent = "";
+const drawClimbProfile = (state: ClimbProfileState): void => {
+  drawOfficialSections(state.canvas, state.sections, resolveOfficialProfileColors());
 };
 
-const drawClimbProfile = (canvas: HTMLCanvasElement, payload: ClimbProfilePayload, sections?: OfficialProfileSection[]): void => {
-  const profileSections = sections ?? climbProfileSections(payload);
-  if (profileSections.length === 0) return;
-  drawOfficialSections(canvas, profileSections, resolveOfficialProfileColors());
+const clearHover = (state: ClimbProfileState): void => {
+  drawClimbProfile(state);
+  state.hoverOutput.textContent = "";
 };
 
 const bindHover = (state: ClimbProfileState): void => {
@@ -85,7 +72,7 @@ const bindHover = (state: ClimbProfileState): void => {
       return;
     }
     const distanceKm = plot.minDistanceKm + ((x - plot.left) / (plot.right - plot.left)) * plot.distanceSpan;
-    drawClimbProfile(state.canvas, state.payload, state.sections);
+    drawClimbProfile(state);
     drawHoverMarker(state, distanceKm);
   });
   state.canvas.addEventListener("pointerleave", () => clearHover(state));
@@ -97,13 +84,11 @@ const init = (): void => {
   const canvas = document.querySelector<HTMLCanvasElement>("[data-climb-profile]");
   if (!payloadElement || !canvas) return;
   const payload = JSON.parse(payloadElement.textContent ?? "null") as ClimbProfilePayload | null;
-  if (!payload || payload.elevations.length < 2) return;
-  const sections = climbProfileSections(payload);
-  if (sections.length === 0) return;
+  if (!payload || payload.sections.length === 0) return;
   const hoverOutput = document.querySelector<HTMLOutputElement>("[data-climb-profile-hover]");
   if (!hoverOutput) return;
-  const state: ClimbProfileState = { canvas, payload, sections, hoverOutput };
-  drawClimbProfile(canvas, payload, sections);
+  const state: ClimbProfileState = { canvas, sections: officialProfileSections(payload.sections), hoverOutput };
+  drawClimbProfile(state);
   bindHover(state);
 };