#3570 [Other] launch --show-key does not know the config generated by setup.py

Beschreibung

UX finding from running the Windows setup flow end-to-end (setup.py -> serve -> launch):

- `setup.py --family coder --model IQ1_M ...` writes the server config as `strata-coder-iq1_m.json` (contains `host`, `api_key`, `max_context`, ...).
- `strata launch --show-key` then does NOT know that config: it does not find/resolve the setup.py-generated file, so the API key cannot be shown or copied for clients.
- Workaround we had to use: parse the JSON ourselves to read the key.

Suggestion: make `launch` (and `--show-key`) resolve configs by the documented naming convention `strata-<model>.json` in the install dir, so users can do:

    strata launch --show-key     -> "key for model coder-iq1_m: <key>"

without hand-reading the config. Bonus: a `--copy-key` or plain hint "key is stored in strata-coder-iq1_m.json" would help first-time LAN users.

Environment: Windows-nativ flow via START-HERE.bat / setup.py, serve on 0.0.0.0:8080 with generated api_key.


Strata version: 0.1.45.3 (engine built from source)