R1: schema & naming reset — squash migrations, rename variants

Squash the 12 goose migrations into one 00001_baseline.sql (there is no prod
data; verified schema-identical to the chain via a pg_dump diff + the green
integration suite) and rename the game-variant labels
english/russian_scrabble/erudit -> scrabble_en/scrabble_ru/erudit_ru across the
backend, the FlatBuffers wire values and the UI.

dawg filenames and the Go enum identifiers are unchanged; the i18n display keys
are kept. Adds PRERELEASE.md (the R1-R7 pre-release tracker), linked from
CLAUDE.md. Contour DB wipe and the scrabble-dictionary tidy are follow-ups.

backend/internal/adminconsole/render_test.go

@@ -20,15 +20,15 @@ func TestRendererRendersEveryPage(t *testing.T) {
 		data any
 		want string
 	}{
-		{"dashboard", DashboardView{Accounts: 3, Variants: []VariantVersions{{Variant: "english", Latest: "v1", Versions: []string{"v1"}}}}, "Dashboard"},
+		{"dashboard", DashboardView{Accounts: 3, Variants: []VariantVersions{{Variant: "scrabble_en", Latest: "v1", Versions: []string{"v1"}}}}, "Dashboard"},
 		{"users", UsersView{Items: []UserRow{{ID: "a1", DisplayName: "Kaya"}}, Pager: NewPager(1, 50, 1)}, "Kaya"},
 		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya", HasStats: true, Stats: StatsRow{Wins: 2}, TelegramID: "123", ConnectorEnabled: true}, "Send Telegram message"},
-		{"games", GamesView{Items: []GameRow{{ID: "g1", Variant: "english", Status: "active"}}, Status: "active", Pager: NewPager(1, 50, 1)}, "g1"},
-		{"game_detail", GameDetailView{ID: "g1", Variant: "english", Seats: []SeatRow{{Seat: 0, DisplayName: "Kaya"}}}, "Seats"},
+		{"games", GamesView{Items: []GameRow{{ID: "g1", Variant: "scrabble_en", Status: "active"}}, Status: "active", Pager: NewPager(1, 50, 1)}, "g1"},
+		{"game_detail", GameDetailView{ID: "g1", Variant: "scrabble_en", Seats: []SeatRow{{Seat: 0, DisplayName: "Kaya"}}}, "Seats"},
 		{"complaints", ComplaintsView{Items: []ComplaintRow{{ID: "c1", Word: "qi", Status: "open"}}, Status: "open", Pager: NewPager(1, 50, 1)}, "qi"},
 		{"messages", MessagesView{Items: []MessageRow{{ID: "m1", SenderID: "a1", SenderName: "Kaya", Source: "telegram", Body: "good luck", GameID: "g1"}}, Pager: NewPager(1, 50, 1)}, "good luck"},
-		{"complaint_detail", ComplaintDetailView{ID: "c1", Word: "qi", Variant: "english"}, "Resolve"},
-		{"dictionary", DictionaryView{Variants: []VariantVersions{{Variant: "english", Latest: "v1", Versions: []string{"v1"}}}, Changes: []DictChangeRow{{Variant: "english", Word: "qi", Action: "add"}}}, "Hot-reload"},
+		{"complaint_detail", ComplaintDetailView{ID: "c1", Word: "qi", Variant: "scrabble_en"}, "Resolve"},
+		{"dictionary", DictionaryView{Variants: []VariantVersions{{Variant: "scrabble_en", Latest: "v1", Versions: []string{"v1"}}}, Changes: []DictChangeRow{{Variant: "scrabble_en", Word: "qi", Action: "add"}}}, "Hot-reload"},
 		{"broadcast", BroadcastView{ConnectorEnabled: true}, "Post to the game channel"},
 		{"message", MessageView{Heading: "Done", Body: "ok", Back: "/_gm/"}, "Done"},
 	}

backend/internal/adminconsole/templates/pages/dictionary.gohtml

@@ -30,9 +30,9 @@
 <form class="form" method="post" action="/_gm/dictionary/changes/apply">
 <label>Mark applied for variant
 <select name="variant">
-<option value="english">english</option>
-<option value="russian_scrabble">russian_scrabble</option>
-<option value="erudit">erudit</option>
+<option value="scrabble_en">scrabble_en</option>
+<option value="scrabble_ru">scrabble_ru</option>
+<option value="erudit_ru">erudit_ru</option>
 </select>
 </label>
 <label>In version <input type="text" name="version" placeholder="v2" required></label>