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/lib/ui/about_screen.dart

@@ -6,10 +6,10 @@ import '../i18n/strings.g.dart';
 import 'theme.dart';
 
 /// The app's public website. Shown as a tappable row in [AboutScreen].
-const String _websiteUrl = 'https://tanemaki.app';
+const String _websiteUrl = 'https://tane.comunes.org';
 
-/// The year Tanemaki's copyright starts. Ğ1nkgo uses its own first year (2023);
-/// Tanemaki's is 2026.
+/// The year Tane's copyright starts. Ğ1nkgo uses its own first year (2023);
+/// Tane's is 2026.
 const int _copyrightStartYear = 2026;
 
 /// A single year (`2026`) until the calendar rolls over, then a range
@@ -22,7 +22,7 @@ String _copyrightYears() {
 }
 
 /// An "about" screen à la Ğ1nkgo: brand header, the human explanation of what
-/// Tanemaki is and where its name comes from, the app version, license, the
+/// Tane is and where its name comes from, the app version, license, the
 /// website, and the bundled open-source licenses page.
 class AboutScreen extends StatelessWidget {
   const AboutScreen({super.key});
@@ -99,7 +99,7 @@ class AboutScreen extends StatelessWidget {
   }
 }
 
-/// Brand block: the logo, the app name and its 種まき kanji.
+/// Brand block: the logo, the app name and its 種 kanji.
 class _Header extends StatelessWidget {
   const _Header();
 
@@ -133,7 +133,7 @@ class _Header extends StatelessWidget {
   }
 }
 
-/// The two explanatory paragraphs: what Tanemaki is, and the heritage of its
+/// The two explanatory paragraphs: what Tane is, and the heritage of its
 /// name (yui / tanomoshi / the paper Plantare).
 class _Paragraph extends StatelessWidget {
   const _Paragraph();

apps/app_seeds/lib/ui/backup_section.dart

@@ -140,7 +140,7 @@ class BackupSection extends StatelessWidget {
         title: t.backup.recoverySheetTitle,
         intro: t.backup.recoveryIntro,
         code: code,
-        suggestedName: 'tanemaki-recovery.pdf',
+        suggestedName: 'tane-recovery.pdf',
       );
       _show(messenger, saved ? t.backup.exportSaved : t.backup.cancelled);
     } on Object {

apps/app_seeds/lib/ui/intro_screen.dart

@@ -26,7 +26,7 @@ class _Slide {
 }
 
 /// The first-run intro carousel (also reachable later from the drawer): a few
-/// swipeable cards explaining what Tanemaki is, how privacy works, how sharing
+/// swipeable cards explaining what Tane is, how privacy works, how sharing
 /// works and the Plantare. [onDone] fires when the user skips or finishes, and
 /// is where the caller marks the intro as seen and leaves the screen.
 class IntroScreen extends StatefulWidget {

apps/app_seeds/lib/ui/inventory_list_screen.dart

@@ -212,7 +212,7 @@ class InventoryListScreen extends StatelessWidget {
       title: t.share.catalogTitle,
       date: dateLabel,
       suggestedName:
-          'tanemaki-catalog-${date.toIso8601String().substring(0, 10)}.pdf',
+          'tane-catalog-${date.toIso8601String().substring(0, 10)}.pdf',
       rows: rows,
     );
     messenger.showSnackBar(

apps/app_seeds/lib/ui/label_print_sheet.dart

@@ -170,7 +170,7 @@ class _LabelPrintSheetState extends State<_LabelPrintSheet> {
     final saved = await getIt<LabelSheetService>().saveLabels(
       labels: labels,
       format: _format,
-      suggestedName: 'tanemaki-labels-${_today()}.pdf',
+      suggestedName: 'tane-labels-${_today()}.pdf',
       rtl: rtl,
     );