Security Auditor findings on PR #611:
Fix 1 (BLOCKING): Remove budget_limit handling from Update() entirely.
PATCH /workspaces/:id uses ValidateAnyToken — any enrolled workspace bearer
could self-clear its own spending ceiling. The dedicated AdminAuth-gated
PATCH /workspaces/:id/budget is the only authorised write path.
Fix 2 (MEDIUM): Strip budget_limit and monthly_spend from Get() response
before c.JSON(). GET /workspaces/:id is on the open router — any caller
with a valid UUID must not read billing data.
Also updates four existing tests in workspace_budget_test.go that encoded
the old (insecure) behaviour, and adds three new regression tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
fce0be30fd