fix(s31): close 1 review BLOCKER — EmbedderConfig registry + --embedder-config, never an import path

src/portfolio_optimiser/run.py

@@ -52,8 +52,11 @@ from portfolio_optimiser.validator import Rejection, ValidatedProposal
 from portfolio_optimiser import okf, outbox
 from portfolio_optimiser.semretrieval import (
     SEMANTIC_WEIGHT_DEFAULT,
+    Embedder,
     FakeEmbedder,
     HybridRanker,
+    build_embedder,
+    load_embedder_config,
 )
 from portfolio_optimiser.verdicts import (
     ExpeLContextProvider,
@@ -258,6 +261,7 @@ async def run_project(
     meter: TokenMeter | None = None,
     live_dry_run: bool = False,
     semantic_retrieval: bool = False,
+    embedder: Embedder | None = None,
 ) -> RunResult | DryRunReport:
     """Run the vertical slice for ONE project. ``client_factory`` is the test-injection seam
     (defaults to the real backend). ``verdict_input`` carries the expert decision/rationale
@@ -395,7 +399,11 @@ async def run_project(
     # of that object — including a subsequent run with the flag OFF. Flag off => ranker stays None
     # => ``retrieve`` falls through to the StructuralRetriever default.
     ranker = (
-        HybridRanker(FakeEmbedder(), similarity, SEMANTIC_WEIGHT_DEFAULT)
+        HybridRanker(
+            embedder if embedder is not None else FakeEmbedder(),
+            similarity,
+            SEMANTIC_WEIGHT_DEFAULT,
+        )
         if semantic_retrieval
         else None
     )
@@ -553,6 +561,7 @@ async def run_portfolio(
     top_k: int = 3,
     meter_factory: Callable[[], TokenMeter] | None = None,
     semantic_retrieval: bool = False,
+    embedder: Embedder | None = None,
 ) -> PortfolioResult:
     """Fan out over a portfolio of independent projects SEQUENTIALLY, composing ``run_project``
     as-is (every project's execution state — meter, debate, retrieval context — is built fresh
@@ -632,6 +641,7 @@ async def run_portfolio(
                 max_tokens=max_tokens,
                 top_k=top_k,
                 semantic_retrieval=semantic_retrieval,
+                embedder=embedder,
                 meter=meter_factory() if meter_factory is not None else None,
             ),
         )
@@ -671,6 +681,13 @@ def main(argv: list[str] | None = None) -> int:
         help="fail-fast dimension scope config (JSON): scopes the run to one cost axis; a "
         "missing or malformed file refuses the run (authoritative startup config, not a RAW inbox)",
     )
+    parser.add_argument(
+        "--embedder-config",
+        default=None,
+        help='fail-fast embedder config (JSON, e.g. {"type": "fake"}): selects the embedder '
+        "used by --semantic-retrieval from a CLOSED registry. Not an import path — a config file "
+        "can never name arbitrary code to load (a new embedder is added as a registry branch)",
+    )
     parser.add_argument(
         "--outbox-dir",
         default=None,
@@ -761,6 +778,7 @@ def main(argv: list[str] | None = None) -> int:
             "--run-id": args.run_id is not None,
             "--dimension-config": args.dimension_config is not None,
             "--semantic-retrieval": args.semantic_retrieval,
+            "--embedder-config": args.embedder_config is not None,
         }
         if any(report_forbidden.values()):
             print(
@@ -824,12 +842,18 @@ def main(argv: list[str] | None = None) -> int:
             goals = load_goal_config(args.goals) if args.goals else None
             ledger = SavingsLedger.load(args.ledger) if args.ledger else None
             dimension = load_dimension(args.dimension_config) if args.dimension_config else None
+            embedder = (
+                build_embedder(load_embedder_config(args.embedder_config))
+                if args.embedder_config
+                else None
+            )
             project_ids = (args.project_id,) if args.project_id is not None else None
             portfolio_result = asyncio.run(
                 run_portfolio(
                     project_ids,
                     args.profile,
                     dimension=dimension,
+                    embedder=embedder,
                     ledger=ledger,
                     goals=goals,
                     semantic_retrieval=args.semantic_retrieval,
@@ -902,6 +926,11 @@ def main(argv: list[str] | None = None) -> int:
                     dimension=(
                         load_dimension(args.dimension_config) if args.dimension_config else None
                     ),
+                    embedder=(
+                        build_embedder(load_embedder_config(args.embedder_config))
+                        if args.embedder_config
+                        else None
+                    ),
                     outbox_dir=args.outbox_dir,
                     run_id=args.run_id,
                     verdict_input={"decision": args.decision, "rationale": args.rationale},
@@ -943,6 +972,11 @@ def main(argv: list[str] | None = None) -> int:
                     dimension=(
                         load_dimension(args.dimension_config) if args.dimension_config else None
                     ),
+                    embedder=(
+                        build_embedder(load_embedder_config(args.embedder_config))
+                        if args.embedder_config
+                        else None
+                    ),
                     outbox_dir=args.outbox_dir,
                     run_id=args.run_id,
                     verdict_input={"decision": args.decision, "rationale": args.rationale},