feat(store): default auto_summarize ON for new users (ADR-018)

Migration 011 flips the auto_summarize column default to TRUE and brings
existing rows (maintainer + current registrations) along. Onboarded friends
now get zero-friction discovery: scheduled discovery (ADR-018) both discovers
AND summarizes new videos, so a user's list fills and summarizes itself
instead of presenting an empty list of manual Summarize buttons.

Safe only because the process-wide caption-fetch rate gate (ADR-014 item 2,
prior commit) now exists — auto + scheduled + multi-user would otherwise
self-inflict 429s every cycle. The down migration reverts the default but
intentionally leaves existing rows as-is (no surprise manual regression on
rollback). RegisterUser already lets the column default drive the value, so
no app change is needed; the account-page manual toggle still works.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/adapters/store/migrate_test.go

@@ -49,13 +49,44 @@ func loginEventsExists(t *testing.T) bool {
 // production during a rollback. The test restores the schema to latest before
 // returning so the shared embedded-postgres stays at HEAD for sibling tests.
 func TestMigration010LoginEventsUpDown(t *testing.T) {
-	newStore(t) // ensure the schema is migrated to latest (010 applied)
+	newStore(t) // ensure the schema is migrated to latest (011 applied)
 	require.True(t, loginEventsExists(t), "login_events must exist at latest migration")
 
 	m := fileMigrator(t)
-	require.NoError(t, m.Steps(-1), "down one migration must drop login_events")
+	// 011 (auto_summarize default) sits above 010; step it down first so the
+	// 010 down/up is exercised in isolation.
+	require.NoError(t, m.Steps(-1), "down 011 must not touch login_events")
+	require.True(t, loginEventsExists(t), "011 down leaves login_events intact")
+
+	require.NoError(t, m.Steps(-1), "down 010 must drop login_events")
 	require.False(t, loginEventsExists(t), "login_events must be gone after the down migration")
 
-	require.NoError(t, m.Steps(1), "up one migration must recreate login_events")
+	require.NoError(t, m.Steps(2), "up must recreate 010 then re-apply 011")
 	require.True(t, loginEventsExists(t), "login_events must be restored after the up migration")
 }
+
+// autoSummarizeDefault reads the users.auto_summarize column default as text
+// ("true"/"false"), so the migration's default flip is verifiable directly.
+func autoSummarizeDefault(t *testing.T) string {
+	t.Helper()
+	var def string
+	require.NoError(t, rawPool(t).QueryRow(context.Background(),
+		`SELECT column_default FROM information_schema.columns
+		  WHERE table_name = 'users' AND column_name = 'auto_summarize'`).Scan(&def))
+	return def
+}
+
+// TestMigration011AutoSummarizeDefaultUpDown proves migration 011 is reversible:
+// up sets the auto_summarize column default to TRUE (ADR-018), down restores
+// FALSE. The down intentionally does not revert existing rows — only the default.
+func TestMigration011AutoSummarizeDefaultUpDown(t *testing.T) {
+	newStore(t) // latest (011 applied)
+	require.Equal(t, "true", autoSummarizeDefault(t), "011 sets the default to TRUE")
+
+	m := fileMigrator(t)
+	require.NoError(t, m.Steps(-1), "down 011 reverts the column default")
+	require.Equal(t, "false", autoSummarizeDefault(t), "default is FALSE after the down migration")
+
+	require.NoError(t, m.Steps(1), "up 011 re-applies the TRUE default")
+	require.Equal(t, "true", autoSummarizeDefault(t))
+}

internal/adapters/store/migrations/011_auto_summarize_default.down.sql

@@ -0,0 +1,5 @@
+-- Revert the column default to FALSE. Existing rows are intentionally NOT
+-- reverted: flipping live users back to manual on a rollback would be a
+-- surprising regression (they may have come to rely on auto). The default change
+-- is the reversible part; data stays as the user left it.
+ALTER TABLE users ALTER COLUMN auto_summarize SET DEFAULT FALSE;

internal/adapters/store/migrations/011_auto_summarize_default.up.sql

@@ -0,0 +1,17 @@
+-- Migration 011: flip auto_summarize default to TRUE (ADR-018, Future-B).
+--
+-- Scheduled discovery (ADR-018) makes Tapir watch unprompted. For onboarded
+-- friends that only delivers zero-friction value if the list also SUMMARIZES
+-- itself — a manual default would mean the scheduler discovers videos a user
+-- still has to click through one by one, which is the empty-list problem again.
+-- So new users default to AUTO. The account-page toggle still lets a user switch
+-- to manual (SetAutoSummarize), so this only changes the out-of-the-box state.
+--
+-- Safe only because the process-wide caption-fetch rate gate (ADR-014 item 2)
+-- now exists: auto + scheduled + multi-user would otherwise self-inflict 429s
+-- every cycle. The gate is the precondition for shipping this default.
+ALTER TABLE users ALTER COLUMN auto_summarize SET DEFAULT TRUE;
+
+-- Bring existing rows (maintainer + any current registrations) onto the new
+-- default so they benefit immediately, not just users created after this point.
+UPDATE users SET auto_summarize = TRUE WHERE auto_summarize = FALSE;

internal/adapters/store/summarize_mode_test.go

@@ -45,6 +45,27 @@ func TestAutoSummarizeRoundTripDefaultsFalse(t *testing.T) {
 	require.False(t, got, "set back to manual round-trips")
 }
 
+func TestRegisteredUserDefaultsAutoSummarizeOn(t *testing.T) {
+	ctx := context.Background()
+	s := newStore(t)
+	resetDB(t, rawPool(t))
+
+	// A real registration creates the users row, so the column default (migration
+	// 011: TRUE) drives the mode — onboarded friends get auto out of the box.
+	id, err := s.RegisterUser(ctx, subjectA, "Alice")
+	require.NoError(t, err)
+
+	got, err := s.GetAutoSummarize(ctx, id)
+	require.NoError(t, err)
+	require.True(t, got, "new registrations default to auto-summarize (ADR-018)")
+
+	// The account-page toggle still works: a user can switch to manual.
+	require.NoError(t, s.SetAutoSummarize(ctx, id, false))
+	got, err = s.GetAutoSummarize(ctx, id)
+	require.NoError(t, err)
+	require.False(t, got, "the manual toggle still flips it off")
+}
+
 func TestRequestSummarizeSetsFlag(t *testing.T) {
 	ctx := context.Background()
 	s := newStore(t)