fix(apps): semaphore fsGroup — schema 1.3.0 podSecurityContext for non-root PVC write

The semaphoreui/semaphore image runs as non-root UID 1001 / GID 0 and writes its
generated config.json into the config dir on boot. A mounted Longhorn PVC is
root:root, so UID 1001 got "permission denied" and the pod crash-looped.

First-class the fix into the render contract (same mechanism the retired
gitea-bootstrap-patch was replaced by): schema 1.3.0 adds an optional pod-level
`podSecurityContext`, emitted verbatim onto spec.template.spec.securityContext by
render.py. Absent => every other app renders byte-identical (verified). semaphore
declares fsGroup=1001 (kubelet group-owns the PVC + adds the supplemental group so
UID 1001 can write) plus runAsUser/runAsGroup/runAsNonRoot pinning the image identity.

render.py selftest extended (verbatim render + absence). L0 (schema+kyverno 17/17),
L1 3/3, lint all green.

Co-Authored-By: Claude Opus 4.8 <[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: 1.2.0 (adds optional per-container env/envFrom/lifecycle for the container kind — k8s EnvVar/EnvFromSource/Lifecycle shapes emitted verbatim onto the app container; unblocks headless-install/DB-backed apps e.g. gitea/nextcloud/semaphore/unifi/minecraft). 1.1.0 added the shape invariant exposure:public => auth.mode!=none (docs/13 v1.1 / docs/15 / R-IDP-02).",
+  "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: 1.3.0 (adds optional pod-level podSecurityContext for the container kind — k8s PodSecurityContext emitted verbatim onto the pod spec; its fsGroup unblocks non-root images e.g. semaphore/UID-1001 writing a mounted Longhorn PVC). 1.2.0 added optional per-container env/envFrom/lifecycle for the container kind — k8s EnvVar/EnvFromSource/Lifecycle shapes emitted verbatim onto the app container; unblocks headless-install/DB-backed apps e.g. gitea/nextcloud/semaphore/unifi/minecraft. 1.1.0 added the shape invariant exposure:public => auth.mode!=none (docs/13 v1.1 / docs/15 / R-IDP-02).",
   "type": "object",
   "additionalProperties": false,
   "required": ["name", "source"],
@@ -125,6 +125,20 @@
         "preStop": { "$ref": "#/$defs/execHandler" }
       }
     },
+    "podSecurityContext": {
+      "type": "object",
+      "description": "Optional pod-level SecurityContext for the container kind (docs/13). Mirrors the k8s PodSecurityContext shape and is emitted verbatim onto the pod spec (spec.template.spec.securityContext). Its primary use is `fsGroup`, which makes a mounted Longhorn PVC group-writable by a non-root image (e.g. semaphore runs as UID 1001 and cannot otherwise write its config PVC). Absent => no pod securityContext (existing apps render byte-identical). Ignored for kind=vm.",
+      "additionalProperties": false,
+      "minProperties": 1,
+      "properties": {
+        "runAsUser": { "type": "integer", "description": "UID the container processes run as." },
+        "runAsGroup": { "type": "integer", "description": "Primary GID the container processes run as." },
+        "runAsNonRoot": { "type": "boolean", "description": "Require the container to run as a non-root UID (validated at admission)." },
+        "fsGroup": { "type": "integer", "description": "Supplemental group applied to mounted volumes so they are group-owned + group-writable (chowned by the kubelet), letting a non-root image write a PVC." },
+        "fsGroupChangePolicy": { "type": "string", "enum": ["Always", "OnRootMismatch"], "description": "When the kubelet recursively applies fsGroup ownership to a volume." },
+        "supplementalGroups": { "type": "array", "items": { "type": "integer" }, "description": "Additional GIDs added to the first process in each container." }
+      }
+    },
     "exposure": {
       "type": "string",
       "description": "internal = LAN-only (internal DNS + Gateway on LAN); public = additionally edge port-forwarded 80/443 (docs/09; R-DNS/R-NET).",