chore(routing): retire haiku from delivery-lifecycle roles (#680)

Haiku can't reliably emit the structured envelopes the lifecycle now
runs on — pass_review's per-AC criteria_verified, delegate's
covers_parent_criteria, the findings ledger. A haiku QA/PM claims, gets
validation-rejected, idles, respawns, and loops without advancing a task
(2026-07-24 live: fe-qa on haiku looped four awaiting_qa tasks to zero
progress). The per-token savings (~2x under the Sonnet-5 promo, 3x after)
are dwarfed by the cost of a review that never completes.

Three coordinated changes: ROLE_MODEL_MAP's qa/documenter defaults move
haiku -> sonnet (the actual source of the live incident); the cost_tiered
developer:low -> haiku seed retires to empty (the floor would upgrade it
anyway); and a structured-verb capability floor upgrades any below-floor
Anthropic assignment to sonnet at resolution — from a pin, a ROLE row,
or a future map edit — in both the assignment and legacy paths.
Non-Anthropic providers are untouched (an Anthropic-tier floor, not a
provider policy). pr_reviewer/auditor stay on opus.

Co-authored-by: Renn F <rennf93@users.noreply.github.com>

tests/unit/models/test_model_map.py

@@ -23,9 +23,12 @@ def test_sonnet_5_is_priced() -> None:
     assert cost > 0.0
 
 
-def test_qa_role_routes_to_haiku() -> None:
-    # Phase 2: QA is mechanical gate work → cheapest tier.
-    assert ROLE_MODEL_MAP["qa"] == "haiku"
+def test_no_lifecycle_role_routes_below_the_structured_verb_floor() -> None:
+    # Retired haiku from lifecycle roles (2026-07-24): a haiku QA/documenter
+    # can't emit the structured review envelopes (criteria_verified, findings)
+    # and loops without passing. No role's default may be a haiku-class tier.
+    for role, model in ROLE_MODEL_MAP.items():
+        assert "haiku" not in model.lower(), f"{role} routes to a below-floor {model}"
 
 
 def test_main_pm_role_routes_to_sonnet() -> None: