fix(ci): kill the false-green base resolution; cover R-SEC-01/02 + R-TEST-06 (L0)

Unblocks the enforced Gitea gate, which correctly BLOCKED this branch on
['R-SEC-01','R-SEC-02','R-TEST-06'] being touched but uncovered. Tests were authored;
the coverage rule was NOT narrowed.

=== THE FALSE GREEN (root cause) ===
`make -C ci gate` locally reported PASS having checked NOTHING. resolve_base() validated
nothing, and EVERY way of failing to find a base degraded silently to an empty touched
set + exit 0: an `HEAD~1` last resort, a two-dot diff fallback masking a failing
three-dot diff, and no check that HEAD is even AHEAD of the base. Run while sitting on
`main` (main == origin/main), `origin/main...HEAD` is empty -> "no changed files vs
base" -> the empty set means run.sh is invoked with NO --requirements -> coverage.py's
--require gate never runs at all. Green by vacuum.

Now: candidates are BASE_REF > GITHUB_BASE_REF > origin/main > main, each verified to
resolve. HEAD~1 and the two-dot fallback are gone. Unresolvable base / no merge base /
failed diff / HEAD-not-ahead -> loud banner, EMPTY stdout, exit 3, and a machine-readable
reason (on-base | no-base | diff-failed). gate.sh turns exit 3 into an UNDECIDED
decision: `on-base` -> "NOT APPLICABLE — no branch under gate" (exit 0 so push-to-main
runs don't break, but it never reads as PASS); `no-base`/`diff-failed` -> BLOCKED. It
also now prints the diff base it used. A stale local main warns (widens, never falsely
greens). Also fixed `make -C ci test`, which was SWALLOWING failing suites.

Regression: ci/tests/touched-requirements-base.test.sh — 31 assertions over 8
throwaway-repo scenarios including the exact false-green case, an already-merged branch,
no base ref, a single-commit repo, bogus BASE_REF, a shallow GITHUB_BASE_REF, and
origin/main-preferred-over-stale-main.

=== NEW L0 STATIC LAYER (conformance/tests/l0-static/) ===
Where docs/14 actually puts these invariants. Each check.sh really executes offline via
`run.sh --layer l0` and is wired into ci/l0.sh, so it runs on every PR. No scaffolds.

R-SEC-01 no-plaintext-secrets (165 assertions / 445 tracked files): .sops.yaml holds only
PUBLIC age recipients; every committed Secret is SOPS-wrapped with a mac and ENC[...]
values; ansible vault.yml files are $ANSIBLE_VAULT; no secret-valued ansible key carries
a literal outside a vault; no PEM key / age secret key / kubeconfig client-key-data is
tracked; Flux declares sops decryption; the disallow-plaintext-secrets policy Enforces
and has a proving `result: fail` row. Exemptions are SELF-POLICING, not path allowlists —
a .example must be referenced by no kustomization and hold only placeholders, and the
Kyverno fixture is exempt ONLY while a test asserts the policy rejects it. Proven against
7 injected violations, including deleting the negative row and weakening Enforce->Audit.

R-SEC-02 least-privilege-rbac (41 assertions): no wildcard apiGroup/resource/verb and no
escalate|bind|impersonate in any in-repo Role/ClusterRole; no ServiceAccount bound to
cluster-admin or a wildcard role; the conformance runner's own test identity is scoped
and holds no rights over RBAC objects; the default-deny/host-namespace/egress-class
policies Enforce and each carry a negative row. Proven against 6 injected violations.

R-TEST-06 spec-immutability-enforced (16 assertions): drives the REAL
ci/spec-immutability.sh against HERMETIC throwaway spec repos and asserts its exit code
in every state — clean-at-pin 0, edits under docs/ or decisions/ 1, untracked addition 1,
unadopted drift 1, explicit pin bump 0, ABSENT spec repo 3 (honest skip, never green),
unpinned SPEC_PIN 1 — plus that gate.sh sets BLOCK=1 on its failure, so the mechanism is
load-bearing. The real spec repo is never written to.

Each check documents what it does NOT cover (runtime decryption, git history, runtime
least-privilege, branch protection) rather than overclaiming. status.py now reads
check.sh too, so a placeholder L0 body still outranks an `executable: true` annotation.

Coverage 37/51 -> 40/51 (11 gaps); executable tests 32 -> 35; scaffold-only stays 5 —
no sixth scaffold was added.

Serves: R-SEC-01, R-SEC-02, R-TEST-01..06.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

conformance/lib/status.py

@@ -287,15 +287,22 @@ def classify_test(t: dict) -> dict:
       executable           annotated `conformance.home.k3s/executable: "true"` and no TODOs.
       executable-untagged  no TODOs and a real runnable body, but the annotation is
                            missing (true of the L1 render tests, which execute a
-                           render-check.sh + golden diff, and of the META self-check).
+                           render-check.sh + golden diff, of the L0 static checks, and
+                           of the META self-check).
                            Counted as executable, and flagged as an annotation gap.
       scaffold             anything else.
     """
     p = Path(t["path"])
     text = p.read_text() if p.is_file() else ""
+    # The offline assertion script a test dir may carry: `render-check.sh` (L1 rendering)
+    # or `check.sh` (L0 static). BOTH are read, so a placeholder body in either one still
+    # downgrades the test to a scaffold — an annotation must never outrank the body,
+    # whichever file the body lives in.
     extra = ""
-    if (p.parent / "render-check.sh").is_file():
-        extra = (p.parent / "render-check.sh").read_text()
+    for script in ("render-check.sh", "check.sh"):
+        sp = p.parent / script
+        if sp.is_file():
+            extra += sp.read_text()
     declared = bool(_EXECUTABLE_RE.search(text))
     has_todo = "TODO" in text or "TODO" in extra
     bm = _BLOCKED_RE.search(text)