Module page template

Every page under modules/ uses these sections, in order. Omit a section only if it genuinely does not apply.

1. Purpose: one or two sentences on what the module is for and who uses it.
2. Install: the package name and any extras.
3. Wiring into a host app: the smallest working integration (settings, dependencies, router mounting).
4. Configuration: settings keys and environment variables, in a table.
5. Key concepts: models, actions, events and scopes the module introduces.
6. Examples: two to four runnable snippets. Every snippet must be checked against the source or tests.
7. Troubleshooting: common failures and fixes.
8. Known issues: not a separate section. Where the code differs from the intended behaviour, put an inline notice next to the behaviour it affects, as described in Documenting known issues.
9. API reference: link to the generated reference page. Do not hand-write signature tables.
10. See also: related modules and guides.