Phase 0 clarification follow-ups + reconcile CI integration seams

Adopt the spec's Phase-0 clarifications (spec now at pin a7fc19f) into the impl:
- schema v1.1: enforce exposure:public => auth.mode!=none (positive+negative tested).
- Kyverno: add longhorn=>size and longhorn=>NOT-reacquirable invariants (R-STATE-02/03).
- Ratify the homelab.keithjackson.dev/* label-key convention (now in spec docs/03).
- R-TEST-06 spec-immutability gate: ci/SPEC_PIN + ci/spec-immutability.sh + gate.sh
  stage + Makefile target + a Gitea job (checks spec repo clean & at pin).
- touched-requirements.sh: conformance tags are the authoritative source.

Reconcile 3 CI seams the CI worker flagged (gate was RED, now GREEN):
- create schemas/validate.sh (SCHEMA_VALIDATE_CMD entrypoint) — L0 schema gate runs.
- fix l1.sh/conformance.sh to run.sh's real interface (fixed _artifacts/ paths; no
  --junit/--coverage) and collect artifacts.
- exec bits on new scripts.

make -C ci gate => PASS (l0 skips locally w/o kyverno binary; green in CI).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

schemas/servicedefinition.schema.json

@@ -2,7 +2,7 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://home.keithjackson.dev/schemas/servicedefinition.schema.json",
   "title": "ServiceDefinition",
-  "description": "Operator-facing onboarding contract for the home k3s + Longhorn platform. One ServiceDefinition per file under catalog/. Captures INTENT; the platform compiles it into concrete resources (see schemas/renderer-contract.md). Canonical source of truth: spec docs/13-service-catalog.md. Serves R-GITOPS-02; ties into R-NET-*, R-STATE-*, R-TLS-*, R-DNS-*, R-OBS-*, R-UPD-*, R-IDP-*. Schema version: 1.0.0.",
+  "description": "Operator-facing onboarding contract for the home k3s + Longhorn platform. One ServiceDefinition per file under catalog/. Captures INTENT; the platform compiles it into concrete resources (see schemas/renderer-contract.md). Canonical source of truth: spec docs/13-service-catalog.md. Serves R-GITOPS-02; ties into R-NET-*, R-STATE-*, R-TLS-*, R-DNS-*, R-OBS-*, R-UPD-*, R-IDP-*. Schema version: 1.1.0 (adds shape invariant exposure:public => auth.mode!=none, docs/13 v1.1 / docs/15 / R-IDP-02).",
   "type": "object",
   "additionalProperties": false,
   "required": ["name", "source"],
@@ -244,6 +244,20 @@
           }
         }
       }
+    },
+    {
+      "$comment": "public exposure must not be unauthenticated: an explicit auth.mode 'none' is disallowed on public services (docs/13 v1.1, docs/15, R-IDP-02). Absent auth defaults to forward-auth at render time, so it is permitted here.",
+      "if": {
+        "required": ["exposure"],
+        "properties": { "exposure": { "const": "public" } }
+      },
+      "then": {
+        "properties": {
+          "auth": {
+            "properties": { "mode": { "not": { "const": "none" } } }
+          }
+        }
+      }
     }
   ]
 }