feat: replace nextjs-config with environment variables (#632)

* chore: remove nextjs-config

* build fix

* update readme

* explicit nextjs env vars + remove feature-unrelated things and obsolete vars from config

* full config removal

* remove force-dynamic from pages

* compile fix

* restore claude-deleted tests

* better .env.example

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Co-authored-by: Igor Loskutov <igor.loskutoff@gmail.com>

www/app/(app)/transcripts/[transcriptId]/_components/TopicList.tsx

@@ -3,10 +3,11 @@ import ScrollToBottom from "../../scrollToBottom";
 import { Topic } from "../../webSocketTypes";
 import useParticipants from "../../useParticipants";
 import { Box, Flex, Text, Accordion } from "@chakra-ui/react";
-import { featureEnabled } from "../../../../domainContext";
 import { TopicItem } from "./TopicItem";
 import { TranscriptStatus } from "../../../../lib/transcript";
 
+import { featureEnabled } from "../../../../lib/features";
+
 type TopicListProps = {
   topics: Topic[];
   useActiveTopic: [