Epic-lead Slice E — Spawn heuristic & opt-in flag (#226)

You are being dispatched from flower Brief #235: Epic-lead Slice E — Spawn heuristic & opt-in flag (#226)

Recall pointer:
- Use recall_brief with id 235 for the full folder if you need provenance.

Target:
- project: flower (/Users/mikeferrara/Documents/code/flower)
- branch: flower/235-epic-lead-slice-e
- worktree: not specified
- kind: fresh

Current brief spec:
# Slice E — Spawn heuristic & opt-in flag

Parent epic: #226. Design: `docs/design/226-epic-lead-orchestration.md` (§Spawn heuristic). **Depends on Slice A (#231).** Target ≤~300 lines. Honors decided fork **#57** (heuristic + judgment).

## Deliverable
1. **`EpicLeadPolicy::recommend(epic): {recommend: bool, reasons: string[]}`** — advisory, over `children_rollup` + `brief_dependencies`. Recommends a lead when ANY:
   - child count ≥ `config('flower.epic_lead.min_children', 3)`.
   - phased: dependency depth ≥ 2 among children (≥1 child `depends_on` another child).
   - fan-out: ≥ N mutually-independent, parallel-dispatchable children.
   - est. multi-hour (>~2h): judgment signal surfaced, MAIN decides.
2. **Per-brief opt-in/opt-out** — `brief.meta.epic_lead ∈ {auto, force, never}` (meta, no migration; recommended for v1). `force` → always spawn; `never` → MAIN inline; `auto` (default) → heuristic + judgment. MAIN's judgment is authoritative over the heuristic in both directions.
3. **Config** — `config/flower.php` `epic_lead` block: `min_children` (3), `max_concurrent` (3), `post_merge_window_minutes` (30).
4. **Surface the recommendation** — show "epic-lead recommended" (+ reasons) in `recall_dispatch_queue` / `/roster` so the operator sees it.

## Tests
- Each threshold trips `recommend` with the right reason; below all + `auto` → no recommend.
- `force`/`never` override the heuristic.
- Policy is advisory only (returns signal, does not spawn).

## Notes
- This slice does not spawn anything — it produces the recommendation MAIN consults. Spawn mechanism is Slice B.

Recent/key trace events:
[1] participant_joined flower-226-worker: (no body)
[2] note_added flower-226-worker: # Slice E — Spawn heuristic & opt-in flag

Design: `docs/design/226-epic-lead-orchestration.md` (§Spawn heuristic). Depends on Slice A. Target ≤~300 lines. Honors decided fork **#57** (heuristic + judgment).

## Deliverable
1. **`EpicLeadPolicy::recommend(epic): {recommend: bool, reasons: string[]}`** — advisory, over `children_rollup` + `brief_dependencies`. Recommends a lead when ANY:
   - child count ≥ `config('flower.epic_lead.min_children', 3)`.
   - phased: dependency depth ≥ 2 among children (≥1 child `depends_on` another child).
   - fan-out: ≥ N mutually-independent, parallel-dispatchable children.
   - est. multi-hour (>~2h): judgment signal surfaced, MAIN decides.
2. **Per-brief opt-in/opt-out** — `brief.meta.epic_lead ∈ {auto, force, never}` (meta, no migration; recommended for v1). `force` → always spawn; `never` → MAIN inline; `auto` (default) → heuristic + judgment. MAIN's judgment is authoritative over the heuristic in both directions.
3. **Config** — `config/flower.php` `epic_lead` block: `min_children` (3), `max_concurrent` (3), `post_merge_window_minutes` (30).
4. **Surface the recommendation** — show "epic-lead recommended" (+ reasons) in `recall_dispatch_queue` / `/roster` so the operator sees it.

## Tests
- Each threshold trips `recommend` with the right reason; below all + `auto` → no recommend.
- `force`/`never` override the heuristic.
- Policy is advisory only (returns signal, does not spawn).

## Notes
- This slice does not spawn anything — it produces the recommendation MAIN consults. Spawn mechanism is Slice B.
[3] parent_set flower-226-worker: Grouped under epic #226.
[4] dependency_added flower-226-worker: Now depends on #231 (Epic-lead Slice A — Lead identity & roster scaffolding (#226)).
[5] plan_proposed flower-226-worker: # Slice E — Spawn heuristic & opt-in flag

Parent epic: #226. Design: `docs/design/226-epic-lead-orchestration.md` (§Spawn heuristic). **Depends on Slice A (#231).** Target ≤~300 lines. Honors decided fork **#57** (heuristic + judgment).

## Deliverable
1. **`EpicLeadPolicy::recommend(epic): {recommend: bool, reasons: string[]}`** — advisory, over `children_rollup` + `brief_dependencies`. Recommends a lead when ANY:
   - child count ≥ `config('flower.epic_lead.min_children', 3)`.
   - phased: dependency depth ≥ 2 among children (≥1 child `depends_on` another child).
   - fan-out: ≥ N mutually-independent, parallel-dispatchable children.
   - est. multi-hour (>~2h): judgment signal surfaced, MAIN decides.
2. **Per-brief opt-in/opt-out** — `brief.meta.epic_lead ∈ {auto, force, never}` (meta, no migration; recommended for v1). `force` → always spawn; `never` → MAIN inline; `auto` (default) → heuristic + judgment. MAIN's judgment is authoritative over the heuristic in both directions.
3. **Config** — `config/flower.php` `epic_lead` block: `min_children` (3), `max_concurrent` (3), `post_merge_window_minutes` (30).
4. **Surface the recommendation** — show "epic-lead recommended" (+ reasons) in `recall_dispatch_queue` / `/roster` so the operator sees it.

## Tests
- Each threshold trips `recommend` with the right reason; below all + `auto` → no recommend.
- `force`/`never` override the heuristic.
- Policy is advisory only (returns signal, does not spawn).

## Notes
- This slice does not spawn anything — it produces the recommendation MAIN consults. Spawn mechanism is Slice B.
[6] participant_joined flower-231-worker: (no body)
[7] unblocked flower-231-worker: Unblocked — #231 reached complete.
[8] participant_joined flower-orchestrator: (no body)
[9] status_change flower-orchestrator: (no body)

Recommended linked context:
{
    "todos": [],
    "scratchpads": []
}

Execution notes:
- Treat the brief as the source of truth.
- Keep work scoped to this dispatch request.
- Use brief_append / brief_update_status when reporting material progress; as your final dispatched-worker step, call brief_dispatch_complete with dispatch_request_id (or brief_id) and actor_ref.
- Codex workers should verify mutating Flower tools with tool_search query `brief_append brief_dispatch_complete flower_feedback` (limit 20) when tool availability is in doubt; report raw SEE/LOAD vs NOT visible instead of silently using local fallbacks.
- Add a git commit trailer `Brief: #235` to every commit for this brief so flower can exact-link commits back to the brief.