docs: tools/CONTRACT.md als Nachschlage-Dokument strukturiert, AGENTS.md-Routing angepasst (schliesst #92)

Files changed:
- AGENTS.md
- CHANGES.md
- VERSION
- tools/CONTRACT.md
- tools/chemenu/tests/test_docs_verify.py

tools/chemenu/tests/test_docs_verify.py

@@ -172,6 +172,47 @@ def test_a_renamed_error_contracts_heading_is_reported_not_silently_scanned(tmp_
     assert not any("§ Error contracts" in issue and "not documented" in issue for issue in issues)
 
 
+def test_a_section_runs_on_past_its_own_subheadings():
+    """`###` groups inside a section must not end it. Both tables are split
+    into per-group subsections, each with its own table header, so a lookahead
+    that stopped at any `#` would truncate § Commands at its first group and
+    report every later command as undocumented."""
+    text = (
+        "## Commands\n\n"
+        "### Pages\n\n| `alpha` | does things |\n\n"
+        "### Git\n\n| `beta` | does other things |\n\n"
+        "## Error contracts\n\n| `gamma` | never | yes | retry |\n"
+    )
+    section = docs_verify.section_text(text, "## Commands")
+    assert docs_verify.documented_commands(section) == ["alpha", "beta"]
+    assert "gamma" not in section
+
+
+def test_grouped_tables_are_still_checked_in_both_directions(tmp_path, monkeypatch):
+    """The section split and the `###` grouping compose: each table is still
+    read as one pot of rows within its own section, however many subsections
+    and table headers it is broken into."""
+    fake = _fake_contract(
+        tmp_path,
+        commands_rows=(
+            "### Pages\n\n| Command | Purpose |\n| `alpha` | does things |\n\n"
+            "### Git\n\n| Command | Purpose |\n"  # `beta`'s row was deleted here
+        ),
+        error_rows=(
+            "### Pages\n\n| `alpha` | never | yes | retry |\n\n"
+            "### Git\n\n| `beta` | never | yes | retry |\n"
+        ),
+    )
+    monkeypatch.setattr(docs_verify, "CLI_README", fake)
+    monkeypatch.setattr(docs_verify, "registered_commands", lambda: {"alpha", "beta"})
+    issues = docs_verify.check_cli_readme()
+    assert any(
+        "beta" in issue and "§ Commands" in issue and "not documented" in issue
+        for issue in issues
+    )
+    assert not any("§ Error contracts" in issue for issue in issues)
+
+
 def test_collection_contracts_exist():
     assert docs_verify.check_collection_contracts() == []