feat(security): Haertung nach OWASP Top 10 (#024)

Drei echte Luecken gefunden und geschlossen:

1. Die 27 Server Actions verliessen sich allein auf proxy.ts. Jede prueft die
   Sitzung jetzt selbst und schlaegt gegen die Datenbank nach, ob das Konto
   noch gilt - damit lassen sich Sitzungen ueberhaupt erst widerrufen.
2. Der Anmelde-Endpunkt prueft die Herkunft des Formulars; vorher war
   Login-CSRF moeglich.
3. Content-Security-Policy mit Nonce je Anfrage und strict-dynamic.

Dazu: npm audit ist ohne Befund (mysql2 und deepmerge-ts per overrides
angehoben statt Prisma zurueckzustufen), eine Benutzerverwaltung fuer die
Kommandozeile und docs/sicherheit.md mit allem, was bewusst offen bleibt -
keine Rollen, keine Zwei-Faktor-Anmeldung.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "proxledger",
-  "version": "0.12.0",
+  "version": "0.14.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "proxledger",
-      "version": "0.12.0",
+      "version": "0.14.1",
       "hasInstallScript": true,
       "dependencies": {
         "@node-rs/argon2": "^2.2.1",
@@ -5071,13 +5071,23 @@
       "license": "MIT"
     },
     "node_modules/deepmerge-ts": {
-      "version": "7.1.5",
-      "resolved": "https://registry.npmjs.org/deepmerge-ts/-/deepmerge-ts-7.1.5.tgz",
-      "integrity": "sha512-HOJkrhaYsweh+W+e74Yn7YStZOilkoPb6fycpwNLKzSPtruFs48nYis0zy5yJz1+ktUhHxoRDJ27RQAWLIJVJw==",
+      "version": "8.0.2",
+      "resolved": "https://registry.npmjs.org/deepmerge-ts/-/deepmerge-ts-8.0.2.tgz",
+      "integrity": "sha512-uqbvqLUMrc6p0MO+WBRtTxY55hmyh94WRwI5a++PZe54X+bfVh59FSN7uWCBCW1CCVjzjnrwzfI8zidE2obMMw==",
       "devOptional": true,
+      "funding": [
+        {
+          "type": "ko-fi",
+          "url": "https://ko-fi.com/rebeccastevens"
+        },
+        {
+          "type": "tidelift",
+          "url": "https://tidelift.com/funding/github/npm/deepmerge-ts"
+        }
+      ],
       "license": "BSD-3-Clause",
       "engines": {
-        "node": ">=16.0.0"
+        "node": ">=16.9.0"
       }
     },
     "node_modules/define-data-property": {
@@ -5133,16 +5143,6 @@
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       }
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-    "node_modules/denque": {
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-      "resolved": "https://registry.npmjs.org/denque/-/denque-2.1.0.tgz",
-      "integrity": "sha512-HVQE3AAb/pxF8fQAoiqpvg9i3evqug3hoiwakOyZAwJm+6vZehbkYXZ0l4JxS+I3QxM97v5aaRNhj8v5oBhekw==",
-      "devOptional": true,
-      "license": "Apache-2.0",
-      "engines": {
-        "node": ">=0.10"
-      }
-    },
     "node_modules/destr": {
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       "resolved": "https://registry.npmjs.org/destr/-/destr-2.0.5.tgz",
@@ -7820,24 +7820,25 @@
       "license": "MIT"
     },
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-      "resolved": "https://registry.npmjs.org/mysql2/-/mysql2-3.15.3.tgz",
-      "integrity": "sha512-FBrGau0IXmuqg4haEZRBfHNWB5mUARw6hNwPDXXGg0XzVJ50mr/9hb267lvpVMnhZ1FON3qNd4Xfcez1rbFwSg==",
+      "version": "3.24.4",
+      "resolved": "https://registry.npmjs.org/mysql2/-/mysql2-3.24.4.tgz",
+      "integrity": "sha512-A2olluVlj0mvgyIRRISMEzXc51m+21mRtcMVjJyIpt2GG98+XrC9m9HzsqcMsX2LcnfccJvY5NB22g8fENBnOA==",
       "devOptional": true,
       "license": "MIT",
       "dependencies": {
-        "aws-ssl-profiles": "^1.1.1",
-        "denque": "^2.1.0",
+        "aws-ssl-profiles": "^1.1.2",
         "generate-function": "^2.3.1",
-        "iconv-lite": "^0.7.0",
-        "long": "^5.2.1",
-        "lru.min": "^1.0.0",
-        "named-placeholders": "^1.1.3",
-        "seq-queue": "^0.0.5",
-        "sqlstring": "^2.3.2"
+        "iconv-lite": "^0.7.3",
+        "long": "^5.3.2",
+        "lru.min": "^1.1.4",
+        "named-placeholders": "^1.1.6",
+        "sql-escaper": "^1.5.1"
       },
       "engines": {
         "node": ">= 8.0"
+      },
+      "peerDependencies": {
+        "@types/node": ">= 8"
       }
     },
     "node_modules/named-placeholders": {
@@ -9059,12 +9060,6 @@
         "semver": "bin/semver.js"
       }
     },
-    "node_modules/seq-queue": {
-      "version": "0.0.5",
-      "resolved": "https://registry.npmjs.org/seq-queue/-/seq-queue-0.0.5.tgz",
-      "integrity": "sha512-hr3Wtp/GZIc/6DAGPDcV4/9WoZhjrkXsi5B/07QgX8tsdc6ilr7BFM6PM6rbdAX1kFSDYeZGLipIZZKyQP0O5Q==",
-      "devOptional": true
-    },
     "node_modules/set-function-length": {
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       "resolved": "https://registry.npmjs.org/set-function-length/-/set-function-length-1.2.2.tgz",
@@ -9314,14 +9309,20 @@
         "node": ">= 10.x"
       }
     },
-    "node_modules/sqlstring": {
-      "version": "2.3.3",
-      "resolved": "https://registry.npmjs.org/sqlstring/-/sqlstring-2.3.3.tgz",
-      "integrity": "sha512-qC9iz2FlN7DQl3+wjwn3802RTyjCx7sDvfQEXchwa6CWOx07/WVfh91gBmQ9fahw8snwGEWU3xGzOt4tFyHLxg==",
+    "node_modules/sql-escaper": {
+      "version": "1.5.2",
+      "resolved": "https://registry.npmjs.org/sql-escaper/-/sql-escaper-1.5.2.tgz",
+      "integrity": "sha512-6CKD38c31SENivxOADeMNLdukOnUxUcflKtzVWzace7Riv1v7cAEym5Cx9Q7gYZ3ezIJI7ZpqecQq8cqNeSSFg==",
       "devOptional": true,
       "license": "MIT",
       "engines": {
-        "node": ">= 0.6"
+        "bun": ">=1.0.0",
+        "deno": ">=2.0.0",
+        "node": ">=12.0.0"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/mysqljs/sql-escaper?sponsor=1"
       }
     },
     "node_modules/stable-hash": {