Close the clawability backlog with deterministic CLI output and lane lineage

Finish the remaining roadmap work by making direct CLI JSON output deterministic across the non-interactive surface, restoring the degraded-startup MCP test as a real workspace test, and adding branch-lock plus commit-lineage primitives so downstream lane consumers can distinguish superseded worktree commits from canonical lineage.

Constraint: Keep the user-facing config namespace centered on .claw while preserving legacy fallback discovery for compatibility
Constraint: Verification needed to stay clean-room and reproducible from the checked-in workspace alone
Rejected: Leave the output-format contract implied by ad-hoc smoke runs only | too easy for direct CLI regressions to slip back into prose-only output
Rejected: Keep commit provenance as free-form detail text | downstream consumers need structured branch/worktree/supersession metadata
Confidence: medium
Scope-risk: moderate
Directive: Extend the JSON contract through the same direct CLI entrypoints instead of adding one-off serializers on parallel code paths
Tested: python .github/scripts/check_doc_source_of_truth.py
Tested: cd rust && cargo fmt --all --check
Tested: cd rust && cargo test --workspace
Tested: cd rust && cargo clippy -p commands -p tools -p rusty-claude-cli --all-targets --no-deps -- -D warnings
Not-tested: full cargo clippy --workspace --all-targets -- -D warnings still reports unrelated pre-existing runtime lint debt outside this change set

rust/crates/commands/src/lib.rs

@@ -2466,6 +2466,7 @@ fn discover_definition_roots(cwd: &Path, leaf: &str) -> Vec<(DefinitionSource, P
     roots
 }
 
+#[allow(clippy::too_many_lines)]
 fn discover_skill_roots(cwd: &Path) -> Vec<SkillRoot> {
     let mut roots = Vec::new();