feat(major2): the hosted surface refuses the proposal review by name and points at the CLI [skip-docs]

Ordre 20260904T173146Z-8102814273-from-portfolio-optimiser, steg 7 av 10.

En PRE-whitelist-sjekk paa raa payload, ETTER isinstance-vakten (en ikke-objekt-body skal
beholde sin 400, ikke bli en 500) og FOER den generiske unknown-field-sjekken, som ellers
ville svart foerst.

Plasseringen er MAALT, ikke valgt: _CONSUMED_FIELDS maa vaere disjunkt fra run_projects
parametre (Fase 4es negative halvdel) mens proposal_reviewer ER en av dem, saa navnet kan
ikke bo i noen av de tre listene. F4-presedensen er IKKE analog - enable_plan_review er en
NOESTET noekkel inne i det whitelistede explore_contract, som er derfor den kan navngis der.

DISKRIMINATOREN ER TEKSTEN, IKKE STATUSEN: whitelisten svarer alt enhver ukjent nokkel med
400 "unknown field(s)", saa en detachet navngitt nekt ville fortsatt gitt 400 med feltnavnet.
Den navngitte meldingen peker paa CLI-doera og paa /readiness, og kontrollen (et ordinaert
ukjent felt) asserterer at den generiske meldingen deler ingenting av det.

Null run_project-kall, ikke bare en 400 (oekt 57).

_response_payload er IKKE utvidet: flaten nekter revieweren, saa feltet kunne kun vaert tomt.

RODT foer impl: tre armer.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_proposal_review_loop_loadbearing.py

@@ -24,6 +24,7 @@ to today, golden transcript included.
 
 from __future__ import annotations
 
+import inspect
 import io
 import json
 import subprocess
@@ -35,7 +36,7 @@ from typing import Any
 import pytest
 from spikes._harness import FakeChatClient, message_texts
 
-from portfolio_optimiser import hitl
+from portfolio_optimiser import hitl, hosting
 from portfolio_optimiser import proposal_review as pr
 from portfolio_optimiser.budget import Budget, BudgetExceeded, TokenMeter
 from portfolio_optimiser.generate import ParseFailure, _build_messages, generate_via_llm
@@ -49,7 +50,8 @@ from portfolio_optimiser.validator import Rejection, ValidatedProposal, proposal
 from portfolio_optimiser.verdicts import VerdictStore
 
 _REPO = Path(__file__).resolve().parents[1]
-_BUNDLE_DIR = _REPO / "shared" / "examples" / "bygg-energi-mikro"
+_EXAMPLES = _REPO / "shared" / "examples"
+_BUNDLE_DIR = _EXAMPLES / "bygg-energi-mikro"
 _PID = "BYGG-KONTOR-NORD"
 _RUN_ID = "proposal-review-door"
 
@@ -1395,3 +1397,61 @@ def test_a_run_with_no_reviewer_prints_no_review_line(
     argv = [a for a in _cli_argv(tmp_path, outbox="outbox") if a != "--proposal-review"]
     assert run.main(argv) == 0
     assert "proposal review" not in capsys.readouterr().out
+
+
+# ---------------------------------------------------------------------------------------------
+# Group D (Steps 7 and 8) — the hosted refusal, and the library dispatcher.
+# ---------------------------------------------------------------------------------------------
+
+
+class _RunProjectRecorder:
+    def __init__(self) -> None:
+        self.calls: list[dict[str, Any]] = []
+
+    async def __call__(self, *args: Any, **kwargs: Any) -> Any:
+        self.calls.append(kwargs)
+        raise AssertionError("run_project must not be reached on a refused invocation")
+
+
+async def test_t21_the_hosted_surface_refuses_the_door_by_name(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """T21 — the hosted refusal. Detach points: deleting the named refusal (M22), forwarding the
+    field instead (M23).
+
+    **The discriminator is the TEXT, not the status.** The whitelist already answers any unknown
+    field with ``400 unknown field(s): …``, so a detached named refusal would STILL return 400
+    naming the field — the arm would pass while the message said nothing about where the door
+    actually is. So the named message points at the CLI and at ``/readiness``, and the control
+    (an ordinary unknown field) asserts the generic message shares none of it.
+
+    Zero ``run_project`` calls, not merely a 400: at the status code a refusal after the spend
+    looks identical to one before it (økt 57's rule)."""
+    recorder = _RunProjectRecorder()
+    monkeypatch.setattr(hosting, "run_project", recorder)
+    payload = {"project_id": _RUN_PID, "docs_dir": str(_BUNDLE_DIR)}
+
+    with pytest.raises(hosting.InvocationRefused) as excinfo:
+        await hosting.invoke({**payload, "proposal_review": True})
+    message = str(excinfo.value)
+    assert "--proposal-review" in message
+    assert "/readiness" in message
+    assert recorder.calls == []
+
+    with pytest.raises(hosting.InvocationRefused) as generic:
+        await hosting.invoke({**payload, "outbox_dir": "/x"})
+    assert "--proposal-review" not in str(generic.value)
+    assert "outbox_dir" in str(generic.value)
+
+
+def test_the_refused_name_enters_neither_half_of_the_whitelist() -> None:
+    """The partition arm. Fase 4e's two asserts (every forwarded field IS a ``run_project``
+    parameter, every consumed field is NOT) must stay untouched, which is why this is a
+    PRE-whitelist check on the raw payload rather than a fourth list entry.
+
+    The F4 precedent is measured as NOT analogous: ``enable_plan_review`` is a NESTED key inside
+    the whitelisted ``explore_contract``, which is why it can be named at all."""
+    assert set(hosting._REFUSED_BY_NAME).isdisjoint(hosting._ALLOWED_FIELDS)
+    assert set(hosting._REFUSED_BY_NAME).isdisjoint(inspect.signature(run_project).parameters)
+    # ...and the parameter it corresponds to is a real one, so the refusal names a door that exists.
+    assert "proposal_reviewer" in inspect.signature(run_project).parameters