stack: SKILL.md-Links auf repo-root-relative Pfade umgestellt, docs verify/instructions verify pruefen Linkziele

Files changed:
- CHANGES.md
- VERSION
- instructions/CONTRACT.md
- instructions/dev/doc-pull-through.md
- instructions/dev/stack-close/SKILL.md
- instructions/dev/stack-dev/SKILL.md
- instructions/wiki-ingest/SKILL.md
- instructions/wiki-lint/SKILL.md
- instructions/wiki-manage/SKILL.md
- instructions/wiki-query/SKILL.md
- instructions/wiki-status/SKILL.md
- tools/CONTRACT.md
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/commands/instructions_cmd.py
- tools/chemenu/tests/test_docs_verify.py
- tools/chemenu/tests/test_instructions_cmd.py

tools/chemenu/tests/test_docs_verify.py

@@ -533,6 +533,72 @@ def test_no_shipped_document_cites_an_issue():
     assert docs_verify.check_no_issue_references() == []
 
 
+def test_a_dead_relative_link_is_reported(tmp_path, monkeypatch):
+    """Regression guard for the bug this check exists to catch: a `../` count
+    wrong for the file's own depth is invisible to every other check - the
+    name it links to is real, the text renders, and nothing resolves the
+    target to notice it lands nowhere."""
+    fake = tmp_path / "example.md"
+    fake.write_text("See [tools/CONTRACT.md](../tools/CONTRACT.md) for the command table.\n", encoding="utf-8")
+    monkeypatch.setattr(docs_verify.toc, "target_files", lambda: [fake])
+    issues = docs_verify.check_reference_targets()
+    assert len(issues) == 1
+    assert "example.md:1" in issues[0]
+    assert "../tools/CONTRACT.md" in issues[0]
+
+
+def test_a_resolving_relative_link_is_not_reported(tmp_path, monkeypatch):
+    (tmp_path / "tools").mkdir()
+    (tmp_path / "tools" / "CONTRACT.md").write_text("# Contract\n", encoding="utf-8")
+    fake = tmp_path / "example.md"
+    fake.write_text("See [tools/CONTRACT.md](tools/CONTRACT.md) for the command table.\n", encoding="utf-8")
+    monkeypatch.setattr(docs_verify.toc, "target_files", lambda: [fake])
+    assert docs_verify.check_reference_targets() == []
+
+
+def test_an_absolute_url_is_not_resolved_as_a_path(tmp_path, monkeypatch):
+    fake = tmp_path / "example.md"
+    fake.write_text("See [Anthropic](https://www.anthropic.com).\n", encoding="utf-8")
+    monkeypatch.setattr(docs_verify.toc, "target_files", lambda: [fake])
+    assert docs_verify.check_reference_targets() == []
+
+
+def test_a_section_anchor_is_stripped_before_resolving(tmp_path, monkeypatch):
+    """CommonMark anchors are not filesystem paths - only the path part of
+    `target#anchor` is checked for existence."""
+    (tmp_path / "kb").mkdir()
+    (tmp_path / "kb" / "CONVENTIONS.md").write_text("## Tone\n", encoding="utf-8")
+    fake = tmp_path / "example.md"
+    fake.write_text("See [kb/CONVENTIONS.md § Tone](kb/CONVENTIONS.md#tone).\n", encoding="utf-8")
+    monkeypatch.setattr(docs_verify.toc, "target_files", lambda: [fake])
+    assert docs_verify.check_reference_targets() == []
+
+
+def test_link_syntax_shown_as_an_example_in_a_fence_is_not_flagged(tmp_path, monkeypatch):
+    """A passage documenting bad link syntax must not be mistaken for a real
+    reference - code fences are masked before scanning, mirroring `toc.py`."""
+    fake = tmp_path / "example.md"
+    fake.write_text(
+        "Do not write it like this:\n\n```markdown\n[gates.md](../nonexistent.md)\n```\n",
+        encoding="utf-8",
+    )
+    monkeypatch.setattr(docs_verify.toc, "target_files", lambda: [fake])
+    assert docs_verify.check_reference_targets() == []
+
+
+def test_every_reference_files_link_targets_resolve():
+    """Forward direction, against the real tree: every relative link in a file
+    `toc.target_files()` covers must resolve - this is what a `../` count
+    wrong for the file's own depth is caught by."""
+    assert docs_verify.check_reference_targets() == []
+
+
+def test_verify_raises_when_a_reference_target_is_dead(monkeypatch):
+    monkeypatch.setattr(docs_verify, "check_reference_targets", lambda: ["dangling"])
+    with pytest.raises(typer.Exit):
+        docs_verify.verify()
+
+
 def test_a_cited_issue_number_is_reported(monkeypatch):
     monkeypatch.setattr(
         docs_verify,