fix(ci): point Server Edition test job at internal/serveredition (not deleted internal/teams) (#680)

The Server Edition CI job (added #631) ran:
  go test -race -tags server ./internal/teams/... ./internal/config/...
But the Teams->Server Edition rename (#603) moved that code to
internal/serveredition/, and #679 deleted the last stale internal/teams/
file. So the job failed with 'lstat ./internal/teams/: no such file or
directory' — and before that, it was silently testing the wrong (stale,
near-empty) path, never the real serveredition packages.

Fix: test ./internal/serveredition/... instead. Verified locally:
go test -race -tags server ./internal/serveredition/... ./internal/config/...
-> all 8 packages ok.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Dumbris

.github/workflows/unit-tests.yml

@@ -204,7 +204,7 @@ jobs:
         run: go build -tags server ./cmd/mcpproxy
 
       - name: Test server edition packages
-        run: go test -race -tags server ./internal/teams/... ./internal/config/...
+        run: go test -race -tags server ./internal/serveredition/... ./internal/config/...
 
   build:
     name: Build