stack: TOC-Scope auf types/ und docs/, Sprachregeln nach AGENTS.md zentralisiert, alle Templates auf Control-Plane-Sprache, --breaking akkumuliert (schliesst #99)

Files changed:
- AGENTS.md
- CHANGES.md
- ENVIRONMENT.md.template
- SOUL.md
- SOUL.md.template
- USER.md.template
- VERSION
- docs/ownership-and-templates.md
- docs/version-model.md
- instructions/CONTRACT.md
- instructions/dev/doc-pull-through.md
- instructions/dev/stack-close/SKILL.md
- instructions/dev/stack-dev/SKILL.md
- instructions/dev/version-parts.md
- instructions/setup-instance.md
- kb/CONVENTIONS.md
- kb/CONVENTIONS.md.template
- kb/concepts/COLLECTION.md
- kb/sources/COLLECTION.md
- tools/CONTRACT.md
- tools/chemenu/commands/types_cmd.py
- tools/chemenu/commands/version_cmd.py
- tools/chemenu/tests/test_toc.py
- tools/chemenu/tests/test_version_cmd.py
- tools/chemenu/toc.py
- tools/chemenu/version.py
- types/comparison.md
- types/concept.md
- types/entity.md
- types/lint-report.md
- types/source.md

instructions/CONTRACT.md

@@ -172,6 +172,12 @@ Scaffold with `tools/wikitool new instruction --name "<name>"`; the contract is
   at all. If that is worth preserving, it is a concept page under `kb/concepts/`, linked from
   here. Where the line runs, and how to test a passage against it: below.
 - **State scope boundaries.** When does this *not* apply, and what to do instead.
+- **Write it in English, and let the agent speak the instance's language.** Both rules, and the
+  line between prose and quoted vocabulary, are stated once in
+  [AGENTS.md § File naming](../AGENTS.md#file-naming). They are named here because this is the
+  step where they are obeyed or lost: nothing checks either mechanically, and an instruction
+  that models a sentence for the user is where the two are easiest to confuse - the model is
+  written in English, the saying of it follows `kb/CONVENTIONS.md`'s `language:`.
 
 ### A skill's H1 is a name, not an imperative