feat: add site settings management with identity and social links

- Add site_identity and social_links database tables
- Implement GET/PUT /api/settings endpoints (GET public, PUT authenticated)
- Replace hardcoded homepage content with database-driven settings
- Add admin settings UI with identity and social links editing

migrations/20260106220216_add_site_settings.sql

@@ -0,0 +1,56 @@
+-- Site identity settings (single row table)
+CREATE TABLE site_identity (
+    id INTEGER PRIMARY KEY CHECK (id = 1), -- Enforce single row
+    display_name TEXT NOT NULL,
+    occupation TEXT NOT NULL,
+    bio TEXT NOT NULL,
+    site_title TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- Trigger for updated_at
+CREATE TRIGGER update_site_identity_updated_at 
+    BEFORE UPDATE ON site_identity
+    FOR EACH ROW 
+    EXECUTE FUNCTION update_updated_at_column();
+
+-- Social links (multiple rows, extensible)
+CREATE TABLE social_links (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    platform TEXT NOT NULL, -- Not an enum for extensibility
+    label TEXT NOT NULL,
+    value TEXT NOT NULL,
+    icon TEXT NOT NULL, -- Icon identifier (e.g., 'simple-icons:github')
+    visible BOOLEAN NOT NULL DEFAULT true,
+    display_order INTEGER NOT NULL DEFAULT 0,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- Index for ordering
+CREATE INDEX idx_social_links_order ON social_links(display_order ASC);
+
+-- Trigger for updated_at
+CREATE TRIGGER update_social_links_updated_at 
+    BEFORE UPDATE ON social_links
+    FOR EACH ROW 
+    EXECUTE FUNCTION update_updated_at_column();
+
+-- Seed default identity
+INSERT INTO site_identity (id, display_name, occupation, bio, site_title)
+VALUES (
+    1,
+    'Ryan Walters',
+    'Full-Stack Software Engineer',
+    'A fanatical software engineer with expertise and passion for sound, scalable and high-performance applications. I''m always working on something new.
+Sometimes innovative — sometimes crazy.',
+    'Xevion.dev'
+);
+
+-- Seed default social links
+INSERT INTO social_links (platform, label, value, icon, visible, display_order) VALUES
+    ('github', 'GitHub', 'https://github.com/Xevion', 'simple-icons:github', true, 1),
+    ('linkedin', 'LinkedIn', 'https://linkedin.com/in/ryancwalters', 'simple-icons:linkedin', true, 2),
+    ('discord', 'Discord', 'xevion', 'simple-icons:discord', true, 3),
+    ('email', 'Email', 'your.email@example.com', 'material-symbols:mail-rounded', true, 4);