refactor: move supabase config to repo root, fix port and env setup

- Move supabase/ from packages/db/ to repo root for simpler CLI usage
- Use custom ports (553xx) to avoid conflicts with other local Supabase instances
- Add --env-mode=loose to turbo dev so root .env vars reach Next.js
- Remove hardcoded --port 3000 from next dev (reads PORT env var instead)
- Add .env.example with Supabase env var placeholders
- Add supabase local state dirs to .gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

supabase/migrations/20240216000004_create_property_likes.sql

@@ -0,0 +1,41 @@
+-- Create property_likes table to track user likes
+CREATE TABLE IF NOT EXISTS property_likes (
+  id TEXT PRIMARY KEY,
+  property_id TEXT NOT NULL REFERENCES properties(id) ON DELETE CASCADE,
+  user_id TEXT NOT NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+
+  -- Ensure a user can only like a property once
+  UNIQUE(property_id, user_id)
+);
+
+-- Enable RLS
+ALTER TABLE property_likes ENABLE ROW LEVEL SECURITY;
+
+-- RLS Policies
+-- Users can view all likes (to see like counts)
+CREATE POLICY "Anyone can view likes"
+  ON property_likes FOR SELECT
+  USING (true);
+
+-- Users can insert their own likes
+CREATE POLICY "Users can create their own likes"
+  ON property_likes FOR INSERT
+  WITH CHECK (user_id = current_setting('app.user_id', true)::TEXT);
+
+-- Users can delete their own likes
+CREATE POLICY "Users can delete their own likes"
+  ON property_likes FOR DELETE
+  USING (user_id = current_setting('app.user_id', true)::TEXT);
+
+-- Create index for efficient querying
+CREATE INDEX IF NOT EXISTS idx_property_likes_property_id ON property_likes(property_id);
+CREATE INDEX IF NOT EXISTS idx_property_likes_user_id ON property_likes(user_id);
+
+-- Function to get like count for a property
+CREATE OR REPLACE FUNCTION get_property_like_count(property_id TEXT)
+RETURNS INTEGER AS $$
+BEGIN
+  RETURN (SELECT COUNT(*)::INTEGER FROM property_likes WHERE property_likes.property_id = $1);
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER STABLE;