feat(fase2b): OKF-navigated bundle context replaces chunk-stuffing

Closes the honest Fase 2a limitation: docs_dir==bundle_dir let keyword
chunk-stuffing leak the verdict's realization rate ("0.82") into the debate /
generation prompt regardless of the ExpeL fold (it surfaced from both
verdict-led-fro.md AND golden.json). The realization signal now reaches the
hypothesis prompt ONLY via the gated ExpeL fold.

- okf.py: bundle_context() + Bundle.context_files render the navigated bundle
  (index + frontmatter + cross-links) as the agent read-context, EXCLUDING
  type: verdict (maalbilde §2/§4). Pure stdlib, still MAF-free.
- datasource.py: bundle_citations() derives first-class citations from the
  navigated non-verdict files.
- run_project: on the bundle path context + citations + debate tools come from
  navigation (tools=[]; navigation replaces query-time RAG); the road path keeps
  chunk-stuffing unchanged.

Load-bearing (maalbilde §7): the marker is upgraded from the minted verdict id
to the realization signal itself. The empty-store control now asserts "0.82"
reaches NO prompt — RED against the pre-2b chunk-stuffing path, green after
navigation (TDD red->green). New okf-level test_bundle_context_excludes_verdict_layer
guards the seam directly.

Suite 133->134 passed, 4 skipped; mypy + ruff check clean. Reverted unrelated
ruff-format drift (backends/budget/verdicts/test_contracts) to keep the diff
surgical.

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

src/portfolio_optimiser/datasource.py

@@ -17,6 +17,7 @@ from typing import Any
 
 from agent_framework import FunctionTool, tool
 
+from portfolio_optimiser.okf import Bundle
 from portfolio_optimiser.provenance import Citation
 from portfolio_optimiser.retrieval import RetrievedChunk, TextSpan, retrieve
 
@@ -36,6 +37,21 @@ def retrieve_chunks(query: str, docs_dir: str, top_k: int = 3) -> list[dict[str,
     return [_chunk_to_dict(c) for c in retrieve(query, docs_dir, top_k)]
 
 
+def bundle_citations(bundle: Bundle) -> list[Citation]:
+    """First-class citations for the OKF-navigated bundle context: one ``Citation`` per non-verdict
+    concept file (exactly the files ``okf.bundle_context`` renders). Whole-file locators, exact by
+    construction (``snippet == body[start:end]``). The verdict layer is deliberately uncited — it is
+    not cost documentation; it enters only via the gated ExpeL fold."""
+    return [
+        Citation(
+            file=f.name,
+            locator=TextSpan(start_index=0, end_index=len(f.body)),
+            snippet=f.body,
+        )
+        for f in bundle.context_files
+    ]
+
+
 def chunk_dict_to_citation(d: dict[str, Any]) -> Citation:
     """Map a structuredContent chunk dict into a first-class ``provenance.Citation``."""
     loc = d["locator"]