fix(docs): use official SLSA SVG badge and add codecov.yml (#66)

* fix(docs): use official SLSA SVG badge with logo in monorepo root

🖥️ IDE: [Cursor](https://cursor.sh)
🔌 Extension: [Claude Code](https://claude.ai/download)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Model-Raw: claude-opus-4-5-20251101

* chore: add codecov.yml for monorepo path configuration

🖥️ IDE: [Cursor](https://cursor.sh)
🔌 Extension: [Claude Code](https://claude.ai/download)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Model-Raw: claude-opus-4-5-20251101

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: nullvariant

README.md

@@ -2,7 +2,7 @@
 
 [![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/nullvariant/nullvariant-vscode-extensions/badge)](https://securityscorecards.dev/viewer/?uri=github.com/nullvariant/nullvariant-vscode-extensions)
 [![OpenSSF Best Practices](https://www.bestpractices.dev/projects/11709/badge)](https://www.bestpractices.dev/projects/11709)
-[![SLSA 3](https://img.shields.io/badge/SLSA-Level_3-green)](https://github.com/nullvariant/nullvariant-vscode-extensions/attestations)
+[![SLSA 3](https://slsa.dev/images/gh-badge-level3.svg)](https://slsa.dev/)
 [![Security](https://github.com/nullvariant/nullvariant-vscode-extensions/actions/workflows/security.yml/badge.svg)](https://github.com/nullvariant/nullvariant-vscode-extensions/actions/workflows/security.yml)
 [![CI](https://github.com/nullvariant/nullvariant-vscode-extensions/actions/workflows/ci.yml/badge.svg)](https://github.com/nullvariant/nullvariant-vscode-extensions/actions/workflows/ci.yml)
 [![codecov](https://codecov.io/gh/nullvariant/nullvariant-vscode-extensions/graph/badge.svg)](https://codecov.io/gh/nullvariant/nullvariant-vscode-extensions)

codecov.yml

@@ -0,0 +1,23 @@
+# Codecov Configuration for Monorepo
+# https://docs.codecov.com/docs/codecov-yaml
+
+coverage:
+  status:
+    project:
+      default:
+        target: auto
+        threshold: 5%
+    patch:
+      default:
+        target: auto
+
+# Fix path mapping for monorepo structure
+fixes:
+  - "out/::" # Remove out/ prefix from paths
+  - "extensions/git-id-switcher/out/::extensions/git-id-switcher/src/" # Map compiled to source
+
+# Ignore test files from coverage
+ignore:
+  - "**/*.test.ts"
+  - "**/test/**"
+  - "**/out/test/**"