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

instructions/dev/doc-pull-through.md

@@ -33,7 +33,7 @@ touched; a row that does not apply needs no action.
 
    | Touched surface | Document(s) that make a claim about it |
    |---|---|
-   | A `wikitool` command's behaviour, flags, or interface | Both tables in [tools/CONTRACT.md](../tools/CONTRACT.md): the command reference row, and its per-command error contract (exit codes, atomicity, retry-safety) |
+   | A `wikitool` command's behaviour, flags, or interface | Both tables in [tools/CONTRACT.md](../../tools/CONTRACT.md): the command reference row, and its per-command error contract (exit codes, atomicity, retry-safety) |
    | A stage's authoring rules (`raw/`, `kb/`, `types/`, `reports/`, `work/`, `tools/`, `instructions/`) | The touched `<stage>/CONTRACT.md` |
    | A rule, gate, or invariant `AGENTS.md` itself states | The relevant `AGENTS.md` section (Invariants, Gates, File naming, Routing, ...) |
    | A workflow, stage, or command a human operates by hand | Whichever of `README.md`, `EVALS.md`, `tools/README.md`, `INSTALL.md`, `DEVELOPMENT.md` names it - AGENTS.md § File naming says which document is for which reader |
@@ -42,7 +42,7 @@ touched; a row that does not apply needs no action.
 
 3. **Do not re-derive what `docs verify` already checks mechanically** - existence, table-row
    membership, ignore-canary state. That enumeration lives once, in
-   [tools/CONTRACT.md](../tools/CONTRACT.md)'s own `docs verify` row; copying it here would be a
+   [tools/CONTRACT.md](../../tools/CONTRACT.md)'s own `docs verify` row; copying it here would be a
    second copy that drifts, the exact failure this instruction exists to describe (Gitea #90).
    This instruction is only about the prose no check reads.