Add duration-aware tracker pattern merging

Trackers sharing a prefix but with materially different lifetimes
(e.g. session vs 1-year) were incorrectly merged into a single
prefix pattern. Port the snap table from cookie-utils.ts into Go
and use it to bucket durations so only trackers that display the
same human-readable lifetime can merge. Update the unique index
to include COALESCE(max_age_seconds, -1) so prefix patterns with
different durations can coexist.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/coredata/migrations/20260506T123706Z.sql

@@ -0,0 +1,18 @@
+-- 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 INDEX idx_tracker_patterns_unique_pattern_per_banner;
+
+CREATE UNIQUE INDEX idx_tracker_patterns_unique_pattern_per_banner
+    ON tracker_patterns (cookie_banner_id, tracker_type, pattern, COALESCE(max_age_seconds, -1));

pkg/coredata/tracker_pattern.go

@@ -149,6 +149,7 @@ func (tp *TrackerPattern) LoadByBannerIDTypeAndPattern(
 	cookieBannerID gid.GID,
 	trackerType TrackerType,
 	pattern string,
+	maxAgeSeconds *int,
 ) error {
 	q := `
 SELECT
@@ -174,6 +175,7 @@ WHERE
 	AND cookie_banner_id = @cookie_banner_id
 	AND tracker_type = @tracker_type
 	AND pattern = @pattern
+	AND COALESCE(max_age_seconds, -1) = COALESCE(@max_age_seconds, -1)
 LIMIT 1;
 `
 
@@ -183,6 +185,7 @@ LIMIT 1;
 		"cookie_banner_id": cookieBannerID,
 		"tracker_type":     trackerType,
 		"pattern":          pattern,
+		"max_age_seconds":  maxAgeSeconds,
 	}
 	maps.Copy(args, scope.SQLArguments())
 
@@ -393,7 +396,7 @@ INSERT INTO tracker_patterns (
 	@created_at,
 	@updated_at
 )
-ON CONFLICT (cookie_banner_id, tracker_type, pattern) DO NOTHING
+ON CONFLICT (cookie_banner_id, tracker_type, pattern, COALESCE(max_age_seconds, -1)) DO NOTHING
 `
 
 	args := pgx.StrictNamedArgs{