feat(page): initial landing page with dev tooling

Pre-launch landing page for The Lofty Project — a 501(c)(4) connecting
creative talent with leftist organizing. Includes hero with blur-in
line-by-line animation, three-pillar section (Talent/Media/Infrastructure),
interest signup buttons, and responsive design with fluid typography.

Tooling: Astro 5, Biome linting/formatting, Lefthook git hooks,
Commitizen with conventional commits, and project documentation.

.env.example

@@ -0,0 +1,2 @@
+# Signup form endpoint (defaults to /api/signup if not set)
+PUBLIC_SIGNUP_ENDPOINT=