feat(setup): final community/thank-you step (#732); fix create-admin button overflow (#730)

#730 — the account step's Create-admin button shared a flex row with Back;
its label + loading spinner exceeded the card width, so the button
overflowed the card outline while submitting (and was fragile for longer
i18n labels). Stack both buttons full-width — the primary always has room
for the spinner now, matching every other wizard step.

#732 — add a final 'community' step, shown once on first-run after
config / no-config, before entering the app. Mission line + four link
cards (report a bug, request a feature, star/share, Buy Me a Coffee),
all target=_blank rel=noopener, and a Finish → Dashboard button. Fully
i18n (en + de). Restore keeps its reload flow (a restored instance is no
longer first-run, so it never reaches this step). Adds .github/FUNDING.yml
so GitHub renders a Sponsor button too.

Verified live: drove the real first-run wizard end to end — stacked
account buttons render inside the card, community step shows the mission
+ all four links, Finish lands on the dashboard.

frontend/src/i18n/locales/de.json

@@ -3572,6 +3572,19 @@
       "finish": "Einrichtung abschließen",
       "saveFailed": "Einige Einstellungen konnten nicht gespeichert werden — Sie können sie in den Einstellungen abschließen."
     },
+    "community": {
+      "subtitle": "Alles bereit",
+      "mission": "PicPeak gibt es, damit Fotografinnen und Fotografen ihre Galerien und Kundendaten selbst besitzen — auf dem eigenen Server, ohne monatliche SaaS-Gebühren. Danke, dass du es ausprobierst.",
+      "bugTitle": "Fehler gefunden?",
+      "bugDesc": "Melde ihn und wir sehen ihn uns an.",
+      "featureTitle": "Wunschfunktion?",
+      "featureDesc": "Sag uns, was PicPeak für dich besser machen würde.",
+      "starTitle": "Gefällt es dir? Erzähl davon",
+      "starDesc": "Empfiehl es anderen Fotografen, teile es und gib dem Projekt einen Stern auf GitHub.",
+      "supportTitle": "Entwicklung unterstützen",
+      "supportDesc": "Optional — spendier mir einen Kaffee, um PicPeak am Leben zu halten.",
+      "finish": "Fertig → Dashboard"
+    },
     "stepOf": "Schritt {{current}} von {{total}}",
     "continue": "Weiter",
     "back": "Zurück",

frontend/src/i18n/locales/en.json

@@ -3468,6 +3468,19 @@
       "finish": "Finish setup",
       "saveFailed": "Some settings could not be saved — you can finish them in Settings."
     },
+    "community": {
+      "subtitle": "You're all set",
+      "mission": "PicPeak exists so photographers can own their galleries and client data — on their own server, without monthly SaaS fees. Thanks for giving it a try.",
+      "bugTitle": "Found a bug?",
+      "bugDesc": "Open an issue and we'll take a look.",
+      "featureTitle": "Want a feature?",
+      "featureDesc": "Tell us what would make PicPeak better for you.",
+      "starTitle": "Like it? Spread the word",
+      "starDesc": "Tell other photographers, share it, and star the project on GitHub.",
+      "supportTitle": "Support development",
+      "supportDesc": "Optional — buy me a coffee to help keep PicPeak going.",
+      "finish": "Finish → Dashboard"
+    },
     "stepOf": "Step {{current}} of {{total}}",
     "continue": "Continue",
     "back": "Back",