fix(serveredition): move orphaned broker connector into serveredition pkg (MCP-2455) (#679)

PR #602 added internal/teams/broker/oauth_connector.go AFTER the Teams->Server
Edition rename (#603) moved internal/teams/ -> internal/serveredition/. The
connector landed in the stale path, in package broker, referencing
CredentialStore/UpstreamCredential as same-package symbols — but those live in
internal/serveredition/broker. Result: 'undefined: CredentialStore' under
-tags server, breaking the Server Edition CI job on main (and therefore on
every open PR after #631 added that job to PR CI).

Fix: git mv the connector + its test into internal/serveredition/broker/ (no
importers of the old path) and delete the now-empty internal/teams/ tree.
Same package, so all refs resolve. No code changes.

Verified: go build -tags server ./... (0), go build ./... (0),
go test -tags server ./internal/serveredition/... (all ok).

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

Author: Dumbris