feat: add Pa11y accessibility testing + migrate GitHub refs to Gitea

- Add Pa11y CI config template (templates/configs/pa11yci.json)
- Replace all github.com/mokoconsulting-tech with git.mokoconsulting.tech/MokoConsulting
- Update .moko-standards governance file

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

templates/configs/pa11yci.json

@@ -0,0 +1,22 @@
+{
+    "defaults": {
+        "standard": "WCAG2AA",
+        "timeout": 30000,
+        "wait": 1000,
+        "ignore": [],
+        "chromeLaunchConfig": {
+            "args": [
+                "--no-sandbox",
+                "--disable-setuid-sandbox"
+            ]
+        }
+    },
+    "urls": [
+        {
+            "url": "http://localhost:8080/",
+            "actions": []
+        }
+    ],
+    "concurrency": 2,
+    "useIncognitoBrowserContext": true
+}