feat: Sign in with OTM styled as the one primary action (v0.6.1)

names has no local accounts, so OTM sign-in is the only door — style
it like the house's primary button instead of a plain text link, with
a muted line underneath about Face ID/Touch ID/passkeys, matching the
shared first-party sign-in standard. No "other ways to sign in" toggle
since there's nothing else to switch to.

Also syncs package-lock.json's stale root version and picks up the
already-declared tailwindcss/postcss/autoprefixer entries it was
missing.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014LCQmFvKshyAJsE8C3B5ET

src/app/globals.css

@@ -419,6 +419,30 @@ h2 {
   text-decoration: underline;
 }
 
+/* The "Sign in with OTM" control, styled like the house's one PRIMARY
+   button (see ".wrap button.primary") so it reads as the lead action it is —
+   this app has no local accounts, so OTM is the only door. */
+.signin.primary {
+  display: inline-flex;
+  align-items: center;
+  border-radius: 9px;
+  padding: 11px 18px;
+  background: var(--accent-dim);
+  border: 1px solid var(--accent-dim);
+  color: #fff;
+  font-weight: 600;
+}
+
+.signin.primary:hover {
+  background: var(--accent);
+  border-color: var(--accent);
+  text-decoration: none;
+}
+
+.signin-hint {
+  margin: 4px 0 0;
+}
+
 .wrap button.linkish {
   background: none;
   border: none;