Phase 4 of #1408 (active_tasks counter). Runtime increment/decrement,
schema column (037), and scheduler enforcement (scheduler.go:312)
already shipped — but the write path from template config.yaml +
direct API was missing, so every workspace silently fell through to
the schema default of 1. Leaders that set max_concurrent_tasks: 3 in
their org template were getting 1 anyway, defeating the entire
feature for the use case it was built for (cron-vs-A2A contention on
PM/lead workspaces).
- OrgWorkspace gains MaxConcurrentTasks (yaml + json tags)
- CreateWorkspacePayload gains MaxConcurrentTasks (json tag)
- Both INSERTs now write the column unconditionally; 0/omitted
payload value falls back to 1 (schema default mirror) so the wire
stays single-shape — no forked column list / goto.
- Existing Create-handler test mocks updated to expect the 11th arg.
- New TestWorkspaceCreate_MaxConcurrentTasksOverride locks the
payload→DB propagation for the leader case (value=3).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>