second pass. medium

SCHEMA.md

@@ -110,8 +110,8 @@ needed to render an activity card in a feed — no timeseries, no full track.
 |---|---|---|---|
 | `id` | string | yes | Unique identifier. See **Activity ID** section. |
 | `title` | string | yes | Human-readable name. May be auto-generated if not in source. |
-| `sport` | string | yes | One of: `cycling`, `running`, `hiking`, `walking`, `swimming`, `other`. |
-| `sub_sport` | string\|null | no | e.g. `road`, `mountain`, `gravel`, `indoor`, `trail`. |
+| `sport` | string | yes | One of: `cycling`, `running`, `hiking`, `walking`, `swimming`, `skiing`, `other`. |
+| `sub_sport` | string\|null | no | e.g. `road`, `mountain`, `gravel`, `indoor`, `trail`, `track`, `nordic`, `alpine`, `open_water`, `pool`. |
 | `started_at` | string | yes | ISO 8601 timestamp with timezone. |
 | `distance_m` | number\|null | no | Total distance in metres. |
 | `duration_s` | integer\|null | no | Total elapsed time in seconds. |
@@ -125,8 +125,12 @@ needed to render an activity card in a feed — no timeseries, no full track.
 | `avg_power_w` | integer\|null | no | Average power in watts. |
 | `source` | string\|null | no | Origin of data. See **Source values**. |
 | `privacy` | string | yes | One of: `public`, `blur_start`, `no_gps`, `private`. |
+| `mmp` | array\|null | no | Mean Maximal Power curve — `[[duration_s, avg_watts], ...]`. |
+| `best_efforts` | array\|null | no | Best efforts by distance — `[[distance_km, time_s], ...]`. |
+| `best_climb_m` | number\|null | no | Best single climb in metres (Kadane's algorithm). |
 | `detail_url` | string\|null | no | Relative or absolute URL to the full activity JSON. |
 | `track_url` | string\|null | no | Relative or absolute URL to the GeoJSON track. `null` if `privacy` is `no_gps`. |
+| `preview_coords` | array\|null | no | Simplified track preview — `[[lon, lat], ...]` for card thumbnails. |
 
 ### Activity ID