feat(evaluation): memoir readiness, judge/replay updates, eval web playground

Add memoir_readiness_service and router tests; extend judge schemas/services, replay_service, and conversation rubric; align story route agent, payload, prompts, and story_pipeline_sync; update agent logging, config, and DI. Document internal-eval; add replayDraft util and PlaygroundPage changes in app-eval-web.

api/app/agents/memoir/story_route_agent.py

@@ -13,7 +13,10 @@ from app.agents.memoir.prompts import (
     get_story_batch_plan_prompt,
     get_story_route_prompt,
 )
-from app.agents.memoir.story_route_payload import build_route_candidate_json
+from app.agents.memoir.story_route_payload import (
+    build_route_candidate_json,
+    sort_stories_for_route,
+)
 from app.core.config import settings
 from app.core.llm_call import LLMCallError, llm_json_call
 from app.core.logging import get_logger
@@ -25,6 +28,105 @@ logger = get_logger(__name__)
 # 超过此数量跳过批量规划（单次路由），避免 prompt 过大
 PLAN_BATCH_MAX_SEGMENTS = 48
 
+# 童年 / 求学 / 家庭：模型与后处理均倾向「少拆分、优先续写」
+APPEND_FIRST_CHAPTER_CATEGORIES = frozenset({"childhood", "education", "family"})
+
+
+def default_append_target_story_id(
+    candidate_stories: list[Story],
+    story_meta: dict[str, dict[str, int]] | None,
+    settings: Any,
+) -> str | None:
+    """排序后的首选续写目标（与路由候选 JSON 顺序一致）。"""
+    if not candidate_stories:
+        return None
+    meta = story_meta or {}
+    ordered = sort_stories_for_route(
+        candidate_stories,
+        meta,
+        summary_min_chars=int(settings.story_route_summary_min_chars),
+    )
+    if not ordered:
+        return None
+    return str(ordered[0].id)
+
+
+def merge_consecutive_new_story_units(
+    units: list[StoryBatchPlanUnit],
+) -> list[StoryBatchPlanUnit]:
+    """将相邻的多个 new_story 单元合并为一个，减少同批碎片叙事。"""
+    if not units:
+        return units
+    out: list[StoryBatchPlanUnit] = []
+    i = 0
+    while i < len(units):
+        u = units[i]
+        if u.decision != "new_story":
+            out.append(u)
+            i += 1
+            continue
+        run_segs: list[str] = list(u.segment_ids)
+        j = i + 1
+        while j < len(units) and units[j].decision == "new_story":
+            run_segs.extend(units[j].segment_ids)
+            j += 1
+        if j > i + 1:
+            out.append(
+                StoryBatchPlanUnit(
+                    segment_ids=run_segs,
+                    decision="new_story",
+                    target_story_id=None,
+                    reason="coalesced_consecutive_new_story",
+                )
+            )
+        else:
+            out.append(u)
+        i = j
+    return out
+
+
+def normalize_batch_plan_reduce_new_story_fragmentation(
+    plan: StoryBatchPlan,
+    ordered_segment_ids: list[str],
+    *,
+    chapter_category: str,
+    candidate_stories: list[Story],
+    valid_story_ids: set[str],
+    story_meta: dict[str, dict[str, int]] | None,
+    settings: Any,
+) -> StoryBatchPlan:
+    """
+    LLM 校验通过后的确定性归一：合并相邻 new_story；在 append-first 类目下若整批只有一个 new 块则改为 append。
+    """
+    units = merge_consecutive_new_story_units(list(plan.units))
+    if (
+        chapter_category in APPEND_FIRST_CHAPTER_CATEGORIES
+        and candidate_stories
+        and len(units) == 1
+        and units[0].decision == "new_story"
+    ):
+        tid = default_append_target_story_id(candidate_stories, story_meta, settings)
+        if tid and tid in valid_story_ids:
+            units = [
+                StoryBatchPlanUnit(
+                    segment_ids=list(ordered_segment_ids),
+                    decision="append_story",
+                    target_story_id=tid,
+                    reason="append_first_whole_batch_fallback",
+                )
+            ]
+    candidate = StoryBatchPlan(units=units)
+    ok, err = validate_story_batch_plan(
+        ordered_segment_ids, candidate, valid_story_ids
+    )
+    if not ok:
+        logger.warning(
+            "batch_plan_normalize_revalidate_failed err={} keep_original",
+            err,
+        )
+        return plan
+    return candidate
+
 
 class StoryBatchPlanUnit(BaseModel):
     """批量写入中的一个单元（连续 segment 块）。"""
@@ -120,6 +222,15 @@ class StoryRouteAgent:
         story_meta: dict[str, dict[str, int]] | None = None,
     ) -> StoryRouteDecision:
         if not llm:
+            fb = default_append_target_story_id(
+                candidate_stories, story_meta, settings
+            )
+            if fb and fb in valid_story_ids:
+                return StoryRouteDecision(
+                    decision="append_story",
+                    target_story_id=fb,
+                    reason="no_llm_default_append",
+                )
             return StoryRouteDecision(
                 decision="new_story",
                 new_story_title=None,
@@ -134,6 +245,15 @@ class StoryRouteAgent:
         )
 
         def _decide_fallback() -> StoryRouteDecision:
+            fb = default_append_target_story_id(
+                candidate_stories, story_meta, settings
+            )
+            if fb and fb in valid_story_ids:
+                return StoryRouteDecision(
+                    decision="append_story",
+                    target_story_id=fb,
+                    reason="parse_error_default_append",
+                )
             return StoryRouteDecision(
                 decision="new_story",
                 new_story_title=None,
@@ -152,8 +272,22 @@ class StoryRouteAgent:
         if decision.decision == "append_story":
             tid = decision.target_story_id
             if not tid or tid not in valid_story_ids:
+                fb = default_append_target_story_id(
+                    candidate_stories, story_meta, settings
+                )
+                if fb and fb in valid_story_ids:
+                    logger.info(
+                        "StoryRoute append 无效 target_story_id={}，回退默认 append {}",
+                        tid,
+                        fb,
+                    )
+                    return StoryRouteDecision(
+                        decision="append_story",
+                        target_story_id=fb,
+                        reason="invalid_target_default_append",
+                    )
                 logger.warning(
-                    "StoryRoute append 无效 target_story_id={}，回退 new_story",
+                    "StoryRoute append 无效 target_story_id={}，且无可用默认目标，回退 new_story",
                     tid,
                 )
                 return StoryRouteDecision(
@@ -204,4 +338,12 @@ class StoryRouteAgent:
         if not ok:
             logger.warning("StoryRouteAgent.plan_batch 校验失败: {}", err)
             return None
-        return plan
+        return normalize_batch_plan_reduce_new_story_fragmentation(
+            plan,
+            ordered,
+            chapter_category=chapter_category,
+            candidate_stories=candidate_stories,
+            valid_story_ids=valid_story_ids,
+            story_meta=story_meta,
+            settings=settings,
+        )