opencode prices and Go limits, settings out of .env

- Fetch prices for opencode (Zen and Go) incl. limits, image input, reasoning,
  long-context tiers and peak-hour/date factors; costs apply them per request
- Record the cost opencode reports per response; track Go allowance in 5h/7d/month
  windows against a provider plan limit (budget table, status overlay)
- Settings → Config file: move values of ${NAME} references into the config
- Examples, presets and forms keep keys in the config instead of .env

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -74,14 +74,16 @@ curl -fsSLO https://git.familie-zink.org/zink/codecraft/raw/branch/main/docker-c
 curl -fsSL --create-dirs -o docker/seccomp-sandbox.json \
   https://git.familie-zink.org/zink/codecraft/raw/branch/main/docker/seccomp-sandbox.json
 curl -fsSL -o .env https://git.familie-zink.org/zink/codecraft/raw/branch/main/.env.example
-$EDITOR .env                    # workspace path, provider keys, time zone
+$EDITOR .env                    # workspace path, port, user id, time zone
 docker compose -f docker-compose.release.yml up -d
 docker compose -f docker-compose.release.yml logs codecraft   # one-time setup code for the first admin
 ```
 
 Open `http://localhost:8787`, enter the setup code and create the admin account. Then add a
-provider under *Settings → Providers & models* – or put the keys into `.env` and reference
-them in the config as `${NAME}`.
+provider under *Settings → Providers & models*. `.env` only holds deployment settings; keys,
+tokens and everything else are set in the UI and stored in the configuration file
+(`${NAME}` references to environment variables still work, and *Settings → Config file* moves
+their values into the file).
 
 **Update:** `docker compose -f docker-compose.release.yml pull && docker compose -f docker-compose.release.yml up -d`.
 Releases are named `vYYYYMM-NNNNN` (a counter per month). Pin one with
@@ -153,6 +155,8 @@ output limit, reasoning effort, extra request options and prices per million tok
   model's fallback.
 - **Concurrency limits:** `max_concurrency` per host or model queues requests for servers that
   process one at a time; waiting time is shown and never counted as model latency.
+- **Prices:** *Fetch prices* fills in prices for OpenRouter and opencode (Zen and Go), including
+  long-context tiers and peak-hour factors, which are applied per request.
 - **Status:** every five minutes each provider's model list is fetched (no tokens used), so
   you see at a glance which hosts answer and which keys are rejected. Saving a provider checks
   it right away, and *Test connection* checks URL and key before you save.