design: human dispatch bypasses the orchestrator - direct-to-worker (default: broadcast!) should flow through the god #44

Sibling of #42, but on the messaging path instead of the ledger: the Command Center's DISPATCH box lets the human deliver a task directly into any worker's inbox, bypassing the orchestrator entirely.

Why that's broken:

1. The default target is broadcast — the same task lands in every worker's inbox at once, and N workers race the same job. The GitHub-issue assign flow even sets broadcast explicitly.
2. It bypasses the god's entire job. The system prompt makes the orchestrator own decomposition, dispatch decisions and the ledgers ("write it as a 4-part contract", "keep board.md and tasks.json accurate") — a direct human dispatch produces none of that: no OBJECTIVE/OUTPUT/TOOLS/BOUNDARIES contract, no card in tasks.json, no board entry. The god's floor awareness silently diverges from reality.
3. The picker even offers the send-only prep assistant, whose inbox nothing ever reads (Direct mail to the send-only prep assistant black-holes - delivered into an inbox nothing ever reads #32's black hole, resolved at the router by fix: enforce the assistant's send-only contract at the router (fixes #32) #33 — but the UI shouldn't aim there in the first place).

The one legitimate need behind the worker picker — "I'd like Pam to do this" — belongs inside the brief to the god, not as a bypass around him.

Proposal: all human dispatch flows through the god.

• The dispatch always mails the god (Task from the human).
• The worker dropdown becomes "suggested owner" — forwarded in the brief as "the human suggests Pam for this — your call as orchestrator". Default: Michael decides.
• broadcast is removed; the assistant leaves the list.
• The god decomposes, writes the card (with assignee), and dispatches with a proper contract — the human's intent arrives with full context instead of around it.

Together with #42 (single-writer over tasks.json) this completes the principle: the human talks to the organization through its manager, not past him.

Implementation: PR follows.