feat(nexus-dev): rewrite nexus-stack skill against real merged code (K-101/103/104/106)

Replaces the K-101 placeholder with prescriptive patterns verified
against nexus-hub main: create_app factory + configure_logging order,
Settings/secret-repr, the visibility.py single-query-path with the
architecture test that bans direct selects, router.run as the only LLM
interface (hard guard + LOCAL_ENDPOINT_ALLOWLIST), session auth via
get_current_user/require_admin (404 for member), audit.record whitelist,
PRIV-5 redaction CONTENT_KEYS, alembic autogenerate flow (name
constraints, hand-add triggers/extensions), and the disposable
pgvector/pg16 CI container strategy. Plugin 0.2.0 -> 0.3.0.

nexus-dev/.claude-plugin/plugin.json

@@ -1,11 +1,17 @@
 {
   "name": "nexus-dev",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "Projekt-Plugin für nexus (Family Knowledge Hub): SDD-Karten-Workflow, Security/Privacy-Invarianten (SICHT/PRIV/fail-closed), Stack-Konventionen, Karten-Command. Für Claude Code Sessions im Repo l.kirchner/nexus-hub.",
   "author": {
     "name": "l.kirchner",
     "url": "https://gitea.luki-net.org/l.kirchner"
   },
   "homepage": "https://gitea.luki-net.org/l.kirchner/nexus-hub",
-  "keywords": ["nexus", "sdd", "fastapi", "privacy", "acl"]
+  "keywords": [
+    "nexus",
+    "sdd",
+    "fastapi",
+    "privacy",
+    "acl"
+  ]
 }