feat: Autorenkonventionen nach Eigentum geschnitten - kb/CONVENTIONS.md, deklarierte Collections (3.0.0)

Files changed:
- .gitea/workflows/ci.yml
- .wikitool-kb.json
- AGENTS.md
- CHANGES.md
- INSTALL.md
- README.md
- VERSION
- instructions/CONTRACT.md
- instructions/dev/testing-conventions.md
- instructions/german-terminology.md
- instructions/kb-profiles.md
- instructions/migrations/3.0.0-authoring-conventions.md
- instructions/private-instance.md
- instructions/setup-instance.md
- instructions/wiki-ingest/SKILL.md
- instructions/wiki-manage/SKILL.md
- kb/CONTRACT.md
- kb/CONVENTIONS.md
- kb/CONVENTIONS.md.template
- kb/comparisons/COLLECTION.md
- kb/concepts/COLLECTION.md
- kb/entities/COLLECTION.md
- kb/sources/COLLECTION.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/commands/dist_cmd.py
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/new_page.py
- tools/chemenu/conventions.py
- tools/chemenu/kb_collections.py
- tools/chemenu/kb_scan.py
- tools/chemenu/provenance.py
- tools/chemenu/sections.py
- tools/chemenu/tests/conftest.py
- tools/chemenu/tests/test_conventions.py
- tools/chemenu/tests/test_dist_cmd.py
- tools/chemenu/tests/test_doctor.py
- tools/chemenu/tests/test_new_page.py
- tools/chemenu/tests/test_types_cmd.py
- types/comparison.md
- types/concept.md
- types/entity.md
- types/source.md
- types/type-spec.md

kb/sources/COLLECTION.md

@@ -1,3 +1,8 @@
+---
+profile: sources
+required_by_stack: true
+---
+
 # kb/sources/ - Collection Contract
 
 One page per ingested source. A source page is the bridge between the untrusted material in
@@ -9,8 +14,14 @@ concluded from it. Where the source is wrong, say what it claims and let the sub
 carry the correction. A source page that has been improved beyond its source is no longer
 evidence for anything.
 
-Inherits [kb/CONTRACT.md](../CONTRACT.md) - naming, tone, linking, provenance and confidence
-are defined there and are not restated here.
+Inherits [kb/CONTRACT.md](../CONTRACT.md) for the rules the stack enforces - linking mechanics,
+provenance, citation, the confidence machinery - and
+[kb/CONVENTIONS.md](../CONVENTIONS.md) for what this instance decided: language, naming forms,
+tone, relationship labels, the confidence rubric. Neither is restated here.
+
+**This collection is `required_by_stack`.** `sources coverage`, `[^cite-id]` resolution and
+`kb/provenance.md` resolve against it by name, so unlike every other collection it may not be
+renamed or dropped - its authoring rules below are the instance's, its existence is not.
 
 ## Types offered