Drop legacy cookies and cookie_patterns tables

These tables were superseded by tracker_patterns and
detected_trackers in migration 20260505T090000Z, which
backfilled all data. The old tables are no longer referenced
by any Go code, GraphQL schema, MCP specification, or CLI
command.

The cookie_source and cookie_pattern_match_type enum types
are retained because tracker_patterns still uses them.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>

Co-authored-by: Émile Ré <nemile.re@gmail.com>

pkg/coredata/migrations/20260513T084412Z.sql

@@ -0,0 +1,16 @@
+-- Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+--
+-- Permission to use, copy, modify, and/or distribute this software for any
+-- purpose with or without fee is hereby granted, provided that the above
+-- copyright notice and this permission notice appear in all copies.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+-- REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+-- AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+-- INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+-- LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+-- OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+-- PERFORMANCE OF THIS SOFTWARE.
+
+DROP TABLE IF EXISTS cookies;
+DROP TABLE IF EXISTS cookie_patterns;