Document how a repository opts in to wiki publishing

Describe the wiki/.publish marker and the prune word, the per-organisation
TOKEN_FOR_GITEA_WIKI without fallback, and the new messages in the
onboarding, credentials and troubleshooting guides and the README. Add the
capability row and regenerate the five English wiki pages with their Danish
and Bahasa Malaysia translations.

Task: MIL-006#5

wiki/Capabilities.md

@@ -6,13 +6,14 @@ English | [Dansk](Capabilities.da) | [Bahasa Melayu](Capabilities.ms)
 
 ## Capabilities
 
-Only the first row is implemented. The rest is planned and tracked in the [Project Plan](https://git.tirsystem.com/TirSystem/github-action/src/branch/main/docs/project-plan.md), which also describes each use case.
+Rows that say Implemented or Guides written exist today. The rest is planned and tracked in the [Project Plan](https://git.tirsystem.com/TirSystem/github-action/src/branch/main/docs/project-plan.md), which also describes each use case.
 
 | Capability | Status |
 | --- | --- |
 | Synchronize repository metadata (Gitea to GitHub mirror) | Implemented in `.gitea/scoped_workflows/`, with offline tests and a validation workflow |
 | Configure and validate workflow credentials | Implemented for the sync workflow: preflight checks both tokens before any change ([guide](Credentials)) |
 | Onboard a repository, manage runners, diagnose failures | Guides written ([onboarding](Onboarding), [troubleshooting](Troubleshooting)); scoped delivery to other repositories not yet verified; brief use cases open (MIL-002) |
+| Publish a repository wiki from `wiki/` (opt-in, delivered to every organization) | Implemented in `.gitea/scoped_workflows/publish-wiki.yml`, with offline tests; the pilot in a second repository is pending (MIL-006) |
 | Shared quality checks | Planned (MIL-003) |
 | Versioned release and publishing | Planned (MIL-004) |