idle-draft: add sample_override config flag to bypass cold-start throttle

Optional config key (default false). When true, research candidates are
offered even at max_unreviewed_research_per_dossier; research_sampled
bookkeeping, mark sampled, and status flags are unchanged so unsampled
items stay visible for later human verification.

Claude-Session: https://claude.ai/code/session_01Lgv4Qn82boNFC1jn8QXSNw

scripts/idle-draft

@@ -683,6 +683,7 @@ def count_open_topic_proposals(repo: Path, dossier: str) -> int:
 def build_ready_queue(repo: Path, config: dict, state: dict, in_flight: set) -> list[dict]:
     candidates: list[dict] = []
     dossiers = config["dossiers"]
+    sample_override = bool(config.get("sample_override", False))
     for idx, dossier in enumerate(dossiers):
         unreviewed = count_unreviewed_research(repo, dossier, state)
         max_unreviewed = config["max_unreviewed_research_per_dossier"]
@@ -693,7 +694,7 @@ def build_ready_queue(repo: Path, config: dict, state: dict, in_flight: set) ->
             files = item_files(repo, dossier, f"{nn}-{slug}")
             entry = get_item_state(state, key)
             wtype, reason = next_work_type_for_item(files, entry)
-            if wtype == "research" and unreviewed >= max_unreviewed:
+            if wtype == "research" and unreviewed >= max_unreviewed and not sample_override:
                 continue
             if wtype is None:
                 continue