Stale provider and locale rules in provider_registry docstring, cubic.yaml and the Ollama compose example #1474

Found during the post-v1.15.0 docs review (2026-10-05, main@a0f6f30).

Three stale statements in non-doc files that contradict the code and the updated docs.

Problem

1. open_notebook/ai/provider_registry.py:14-18 (module docstring): "One place still needs a manual edit when adding a provider … the SupportedProvider Literal in api/models.py". There are four manual edits besides the registry: the SupportedProvider Literal (api/models.py), PROVIDER_CONFIG in open_notebook/ai/key_provider.py, env_var_map in get_provider_availability() (api/routers/models.py), and the discovery entry in open_notebook/ai/model_discovery.py. The full list is in docs/7-DEVELOPMENT/change-playbooks.md ("Playbook: Add an AI Provider").
2. cubic.yaml:59-64 (review bot rules): says i18n keys must exist in "ALL 7 locales (en-US, pt-BR, zh-CN, zh-TW, ja-JP, ru-RU, bn-IN)"; frontend/src/lib/locales/ has 13 (adds ca-ES, de-DE, es-ES, fr-FR, it-IT, pl-PL, tr-TR). It repeats the "registry + Literal only" provider rule from item 1, so the bot reviews provider PRs against an incomplete checklist.
3. examples/docker-compose-ollama.yml:10: the usage comment says docker exec open_notebook-ollama-1 ollama pull mistral. That container name only exists when the folder is named open_notebook, and the file sets no container_name. (Its OLLAMA_API_BASE line is tracked separately in [Bug]: Remove OLLAMA_API_BASE dependency in docker-compose.yaml #1229.)

Suggested fix

1. Rewrite the docstring paragraph to point to the playbook instead of counting edits ("adding a provider also needs edits outside this file; see docs/7-DEVELOPMENT/change-playbooks.md").
2. In cubic.yaml: "the key must exist in every locale under frontend/src/lib/locales/" (no count, no list), and replace the provider rule with a pointer to the playbook's step table.
3. Use docker compose exec ollama ollama pull mistral, which works from any folder.

Acceptance

• None of the three files states a fixed locale count or a "one manual edit" rule.
• The Ollama example's pull command works when the compose file lives in a folder with any name.