feat(fase2): wire Step-1 ExpeL retrieval into the hypothesis prompt

Closes maalbilde §5 gap #1 (the one missing "feedback-into-prompt" dataflow)
for the OKF-bundle path. Before, ExpeL was computed AFTER generation into a
discarded SessionContext, so a prior verdict could not influence any hypothesis
(context_providers=0).

- New okf.py: framework-neutral OKF bundle navigation (index + frontmatter +
  cross-links), pure stdlib, no agent_framework/mcp (D7-portable), enforced by
  test_okf_is_maf_free.
- verdicts.py: seed_store_from_bundle + bundle_candidate_features build the
  ExpeL substrate + the pre-hypothesis query key from a bundle.
- run_project(bundle_dir=...): folds the candidate's prior verdicts into the
  generation context BEFORE generate_via_llm; the road path is unchanged.

Load-bearing (maalbilde §7): test_step1_expel_loadbearing proves a prior verdict
reaches the hypothesis prompt and goes RED when the fold is detached (shown via
TDD red->green). The marker is the minted verdict id (content hash) because
docs_dir==bundle_dir lets keyword chunk-stuffing leak the realization rate;
clean layer separation is Fase 2b.

Suite 121->133 passed; mypy + ruff check clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MHR8iKxJRxDiDfNw8HZmWE

src/portfolio_optimiser/verdicts.py

@@ -21,9 +21,12 @@ from __future__ import annotations
 import hashlib
 import json
 from dataclasses import dataclass
+from typing import Any
 
 from agent_framework import ContextProvider, SessionContext
 
+from portfolio_optimiser import okf
+
 # Weights: the affected cost-code overlap dominates, then measure type, then magnitude.
 _W_CODES, _W_MEASURE, _W_MAGNITUDE = 0.60, 0.25, 0.15
 _MAGNITUDE_BUCKETS = [(0.0, 1e5), (1e5, 5e5), (5e5, 1e6), (1e6, float("inf"))]
@@ -196,3 +199,58 @@ def seed_store() -> VerdictStore:
             for vid, codes, mtype, saving, decision, desc in rows
         ]
     )
+
+
+# --- OKF-bundle seeding (Fase 2a): turn a project's bundle into the ExpeL substrate ---
+
+
+def _features_from_ir(ir: dict[str, Any]) -> ProposalFeatures:
+    """Map a bundle's IR projection (``validator-input.json``) to the structural features the
+    store ranks on: the affected cost-code set, the measure string, and the claimed magnitude."""
+    return ProposalFeatures(
+        affected_codes=frozenset(item["code"] for item in ir["affected_items"]),
+        measure_type=ir["measure"],
+        claimed_saving_nok=ir["claimed_saving_nok"],
+        description=ir.get("measure", ""),
+    )
+
+
+def bundle_candidate_features(bundle_dir: str) -> ProposalFeatures:
+    """The pre-hypothesis ExpeL query key: the candidate measure's structural features, read from
+    the OKF bundle's IR projection. Available BEFORE any proposal is generated — which is what lets
+    Step-1 retrieve prior verdicts and fold them into the hypothesis prompt (målbilde §2 step 1)."""
+    return _features_from_ir(okf.load_ir_projection(bundle_dir))
+
+
+def _verdict_rationale(fm: dict[str, str]) -> str:
+    """Build the few-shot rationale from a ``type: verdict`` file's frontmatter, carrying the
+    learning signal the deterministic validator cannot compute (the realization rate + expected
+    actual). This is the ExpeL signal that must reach the next hypothesis."""
+    base = fm.get("description", "")
+    signal = [
+        f"{label}={fm[key]}"
+        for key, label in (
+            ("realization_rate", "realiseringsgrad"),
+            ("expected_actual_saving_nok", "forventet_faktisk_NOK"),
+        )
+        if fm.get(key)
+    ]
+    return f"{base} [{'; '.join(signal)}]" if signal else base
+
+
+def seed_store_from_bundle(bundle_dir: str) -> VerdictStore:
+    """Build a ``VerdictStore`` from an OKF bundle's ``type: verdict`` files. Each verdict is keyed
+    on the bundle's candidate features (so it retrieves for that measure) and carries the
+    realization signal in its rationale. The seed verdict stands in for the durable HITL verdict a
+    real expert would supply via the same folder interface (målbilde §3)."""
+    features = bundle_candidate_features(bundle_dir)
+    bundle = okf.navigate_bundle(bundle_dir)
+    verdicts = [
+        capture_verdict(
+            features,
+            vf.frontmatter.get("decision", "approved"),
+            _verdict_rationale(vf.frontmatter),
+        )
+        for vf in bundle.verdicts
+    ]
+    return VerdictStore(verdicts=verdicts)