Add Note Sharing feature.

migrations/add_note_sharing.sql

@@ -0,0 +1,21 @@
+-- Add note_share table for public note sharing functionality
+CREATE TABLE IF NOT EXISTS note_share (
+    id SERIAL PRIMARY KEY,
+    note_id INTEGER NOT NULL REFERENCES note(id) ON DELETE CASCADE,
+    token VARCHAR(64) UNIQUE NOT NULL,
+    expires_at TIMESTAMP,
+    password_hash VARCHAR(255),
+    view_count INTEGER DEFAULT 0,
+    max_views INTEGER,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    created_by_id INTEGER NOT NULL REFERENCES "user"(id),
+    last_accessed_at TIMESTAMP
+);
+
+-- Create indexes for better performance
+CREATE INDEX IF NOT EXISTS idx_note_share_token ON note_share(token);
+CREATE INDEX IF NOT EXISTS idx_note_share_note_id ON note_share(note_id);
+CREATE INDEX IF NOT EXISTS idx_note_share_created_by ON note_share(created_by_id);
+
+-- Add comment
+COMMENT ON TABLE note_share IS 'Public sharing links for notes with optional password protection and view limits';