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

CLAUDE.md

@@ -29,6 +29,12 @@ Python ≥3.10. MAF (`agent-framework-core` 1.9.0). Pakkehåndtering: `uv`. To b
   `shared/`-kjernen er ren stdlib — null `agent_framework`/`mcp`-import, så samme bundles
   konsumeres uendret av begge stacker (D7-portabel). Håndhevet av
   `tests/test_okf.py::test_okf_is_maf_free`; importér aldri MAF inn i kontekst-laget.
+- **OKF-navigert bundle-kontekst (ikke stuffing):** på bundle-stien bygges agent-lese-konteksten
+  ved å NAVIGERE bundelen (`okf.bundle_context`: index + frontmatter + cross-links, progressiv
+  disclosure) — aldri keyword-chunk-stuffing (målbilde §2/§4). `type: verdict`-laget ekskluderes
+  fra denne konteksten: tidligere dommer når hypotese-prompten KUN via den gatede ExpeL-folden.
+  Load-bearing: `test_bundle_context_excludes_verdict_layer` + empty-store-kontrollen i
+  `test_step1_expel_loadbearing.py` (realiseringssignalet lekker aldri inn via kontekst).
 - **Stoppkriterier + budsjett-tak påkrevd ved oppstart** (fail-fast, aldri ubegrenset loop).
 - **Group Chat maker-checker** som debatt-default (IKKE Magentic, som er eksperimentell).
 - **Kostnadsdisiplin:** utvikle primært på lokal profil (gratis); Foundry/Azure (privat tenant finnes) kun til målrettet, minimal verifisering; billigste modeller + små syntetiske data + harde token-tak. Ingen tunge test-kjøringer.