refactor(branding): rename app Tanemaki → Tane

Public name is now Tane (種, "seed"); Tanemaki (種まき, "to scatter seeds")
is kept only as etymology in the About screen and onboarding.

App not yet distributed, so format tokens rename cleanly with no migration:
backup extension .tanemaki→.tane, QR scheme tanemaki://→tane://, file
prefixes tane-*. Website link and species-catalog User-Agent →
tane.comunes.org. Android label capitalised to "Tane".

Identity/crypto constants already use org.comunes.tane (derivation, HKDF
backup, sync namespace, TANE1 recovery tag) — left untouched, so keys,
backups and sync are unaffected. Tests updated; analyze + full suite green.

apps/app_seeds/android/app/src/main/AndroidManifest.xml

@@ -6,7 +6,7 @@
          asks the user at runtime). -->
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
     <application
-        android:label="tane"
+        android:label="Tane"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">
         <activity