diff --git a/.gitignore b/.gitignore
index 0c395504..ad3a19be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -346,3 +346,24 @@ FodyWeavers.xsd
 Output/
 *.lscache
 test_ws.py
+
+# Internal fork workflow docs — never reach upstream PRs
+CLAUDE.md
+AGENTS.md
+STYLE.md
+docs/PR_WORKFLOW.md
+docs/CONTRIBUTING.md
+PLAN_*.md
+
+# Internal scratch and analysis files
+diff.txt
+merge-analysis.txt
+*.diff
+pr*.txt
+
+# Development diary — private, never reaches upstream
+DIARY.md
+
+# Internal tooling state
+.claude/
+.serena/
diff --git a/NuGet.Config b/NuGet.Config
new file mode 100644
index 00000000..4e800bf6
--- /dev/null
+++ b/NuGet.Config
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
+  </packageSources>
+  <packageSourceMapping>
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+  </packageSourceMapping>
+</configuration>