feat: contact form — method selector, zod validation, Nostr delivery

ContactForm wires vee-validate + zod against the inquiry payload:
optional name, required method (Email/WhatsApp/Signal/Telegram/Nostr),
contact value validated per method (email regex, phone-or-handle,
@handle, npub1 prefix), and a 10-2000 char message. On submit the
form calls submitInquiry() from the Nostr feature and toasts the
result — partial relay acceptance still counts as success and is
surfaced to the visitor.

PrivacyBlurb sits above the form explaining the model in plain
language: encrypted in the browser, delivered through Nostr, no
server in between. Lock icon plus terse copy — the goal is to put a
non-Nostr-native visitor at ease without a wall of jargon.

.env.example documents the two build-time vars (VITE_OWNER_NPUB,
VITE_NOSTR_RELAYS) the form depends on.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.env.example

@@ -0,0 +1,15 @@
+# Earth Walker Design — site env vars
+#
+# Both are inlined at build time by Vite. To rotate either, edit
+# values here, then rebuild + redeploy.
+
+# The Nostr public key that receives encrypted inquiry submissions.
+# Bech32 npub1... form. Generate via `nak key generate` (fiatjaf/nak)
+# or any Nostr client.
+VITE_OWNER_NPUB=
+
+# Optional. Comma-separated wss:// relay URLs the inquiry form
+# publishes to. If unset, defaults to:
+#   wss://relay.damus.io,wss://nos.lol,wss://relay.nostr.band
+# The submission succeeds if at least one relay accepts the event.
+VITE_NOSTR_RELAYS=