V3-14: GPX <type> from activity (code only)

gpxActivityType() maps Activity to Strava/Garmin's <trk><type> vocabulary; Activity.other omits the element rather than writing it empty. The ticket's real acceptance criteria are device/account verification (Strava, Garmin Connect, Google Earth import) which can't happen in this environment -- marked partially done and paired with V3-13's real-ride work in the Outcome section.

docs/v3/README.md

@@ -30,7 +30,7 @@ backup are v4 — see [../BACKLOG.md](../BACKLOG.md).
 | [V3-11](V3-11-offline-tiles.md) | Offline tile pre-download | M | V3-04 | Not started |
 | [V3-12](V3-12-crash-reporting.md) | Crash reporting | S | — | Not started |
 | [V3-13](V3-13-real-ride-measurements.md) | Real-ride measurements | M | **riding** | Not started |
-| [V3-14](V3-14-gpx-interop.md) | GPX interoperability | S | V3-01 | Not started |
+| [V3-14](V3-14-gpx-interop.md) | GPX interoperability | S | V3-01 | Partially done (code only; needs real-device verification) |
 | [V3-15](V3-15-auto-pause.md) | Auto-pause | M | V3-13 *(gated)* | Not started |
 | [V3-16](V3-16-visual-identity.md) | Visual identity | M | V3-04, V3-05 | Not started |
 

docs/v3/V3-14-gpx-interop.md

@@ -1,6 +1,6 @@
 # V3-14 — GPX interoperability
 
-**Phase** Quality · **Depends on** V3-01 for `<type>` · **Size** S · **Status** Not started
+**Phase** Quality · **Depends on** V3-01 for `<type>` · **Size** S · **Status** Partially done
 
 ## Goal
 Confirm an exported ride actually imports into Strava, Garmin Connect and Google Earth —
@@ -49,3 +49,32 @@ Silently breaking the parity harness by changing export output. Update it delibe
 
 ## Out of scope
 GPX import into Rippr. FIT and TCX formats.
+
+## Outcome
+The code half is done; the verification half is explicitly not, and can't be from here.
+
+`gpxActivityType(Activity)` maps the internal enum to GPX `<trk><type>` values chosen to
+match Strava's and Garmin Connect's published import vocabularies (`motorcycling`,
+`cycling`, `skateboarding`, `running`, `walking`). `Activity.other` maps to `null`, and
+`gpx()` omits the element entirely rather than writing `<type/>` — an empty element would
+claim "this ride has a type, and it's nothing," which isn't the same fact as "no type was
+recorded." Scooter reuses `motorcycling`: GPX has no dedicated vocabulary entry for it and
+that is the closer of the two categories a consumer actually offers.
+
+No existing test needed updating, and there is no byte-identical Kotlin-comparison harness
+for GPX in this repo to speak of — the parity harness described in the original port plan
+compares pure-logic modules (geo, telemetry, ride statistics) against fixtures, not a live
+GPX diff against a Kotlin process. `<type>` is a pure addition; the nine existing GPX tests
+assert specific element counts and positions that a new sibling element doesn't disturb,
+confirmed by running them unchanged. Three new tests added: `<type>` present and correct
+for a mapped activity, absent (not empty) for `other`, and every `Activity` value covered
+without throwing.
+
+**Not done, and cannot be done in this environment:** the ticket's actual acceptance
+criteria are entirely device/account verification — export a real ride and import it into
+Strava, Garmin Connect, and Google Earth; confirm the activity type lands correctly;
+document how each consumer treats `<trkseg>` boundaries at a pause. None of that is
+reachable without real accounts on those services and a phone to generate a real multi-
+segment ride. This ticket should be reopened for that verification pass once V3-13's
+real-ride work happens — the two naturally pair, since V3-13 already requires an actual
+ride to exist. `flutter analyze` clean; full suite green (257 tests, up from 254).