feat: Detect mountain pass crossings, name climbs after passes, render ride charts

- osmpass: extract mountain_pass=yes nodes from an OSM PBF, enrich centcols passes with OSM coordinates, resumable -fetch-osm download
- mountain_pass: DetectCrossings for a ride, MatchClimb to name a climb after the pass it tops
- ride: expose Points(), add Climb.Top() and Climb.Name
- chart: -chart renders elevation profile with climb bands and pass markers
- commands: -fetch-osm, -extract-osm, -import-cached, -enrich

1 files changed, 18 insertions, 1 deletions

diff --git a/README.md b/README.md
index 97c022e..06af5d3 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@ A Go toolkit for analyzing cycling rides from GPX exports: parse rides, detect c
 - **Difficulty score (Cotacol)** — scores any ride or climb by splitting it into 100 m segments and summing `0.1 km × slope²` per segment
 - **Similar-climb matching** — finds the same climb across rides by matching start/end coordinates, so times can be compared
 - **Mountain pass download** — imports French mountain passes from centcols.org into a SQLite database
+- **Pass crossing detection** — enriches passes with OSM coordinates, flags which passes a ride crosses, and names each climb after the pass it tops (e.g. "Col de Castellaras")
 - **Plots** — renders elevation and score-profile charts as PNG
 
 ## Getting started
@@ -29,6 +30,18 @@ go build -o biking_home .
 # Run the climb-similarity and difficulty-score demo on the example rides
 ./biking_home -demo
 
+# Import cached department CSVs (debug_department_06.csv, 13.csv) into the DB
+./biking_home -import-cached
+
+# Extract mountain passes from a France OSM PBF into the DB
+./biking_home -extract-osm /path/to/france-latest.osm.pbf
+
+# Backfill OSM coordinates onto passes (needs -extract-osm run first)
+./biking_home -enrich
+
+# Render an elevation chart with climb highlights and pass markers
+./biking_home -chart examples/2023-06-17.AlpesVerdonTour.gpx
+
 # Profile the demo with Go's CPU profiler
 ./biking_home -demo -cpuprofile /tmp/cpu.prof
 ```
@@ -39,6 +52,10 @@ go build -o biking_home .
 | --- | --- | --- |
 | `-download` | Download mountain passes into the database | `false` |
 | `-resume` | Skip departments already cached on disk | `false` |
+| `-import-cached` | Import cached department CSVs into the database | `false` |
+| `-extract-osm` | Extract mountain passes from a France OSM PBF | `""` |
+| `-enrich` | Backfill OSM coordinates onto passes | `false` |
+| `-chart` | Render an elevation chart (climbs + passes) for a GPX file | `""` |
 | `-demo` | Run the climb-similarity demo | `false` |
 | `-cpuprofile` | Write a CPU profile to file | `""` |
 
@@ -47,6 +64,7 @@ go build -o biking_home .
 - Go 1.23; SQLite via `mattn/go-sqlite3`; charts via `gonum.org/v1/plot`
 - `ride` — GPX parsing, climb detection, difficulty scores (KOM + Cotacol), similarity index
 - `mountain_pass` — centcols.org department CSV download into SQLite, with disk caching and retries
+- `osmpass` — OSM PBF extraction (`mountain_pass=yes` nodes) and pass coordinate enrichment
 - **Notable choices** — the difficulty score follows the Cotacol method: the ride is split into fixed 100 m segments and each scores `distance_km × slope²`, so steep sections weigh exponentially more than long flat ones
 
 ## Development
@@ -60,7 +78,6 @@ go test ./...
 
 - Compute estimated power
 - Export data from Strava / Garmin (GPX, TCX, FIT)
-- Auto-detect when a mountain pass is crossed
 - Plot speed and slope per segment, colored by heart rate
 - Persist the chosen climb variant across activities
 - Handle historical data