feat(toolbox): T6 创作工具箱通用生成器框架 — 8 新生成器 + 声明驱动落地页 + P2 收尾

通用执行路径驱动全部生成器（"加生成器=加一份声明"）：
- @llm: ww_agents +7 输出 schema + 7 spec（book-title/blurb/name/golden-finger/
  glossary/opening/fine-outline，只声明 tier）+ build_outline_chapter_context
- @backend: ww_skills GeneratorTool 描述符 + TOOLBOX(11) + get_tool；3 通用端点
  GET /skills/toolbox · POST .../skills/{tool_key}/generate(预览不写库,仅记账) ·
  POST .../ingest(复用 continuity 409 + partition_writes 白名单)；纯 context 派发
- @frontend: 工具箱落地页 RSC + 声明驱动 GeneratorRunner + lib/toolbox 纯函数
  + LeftNav「工具箱」+ ⌘K nav-toolbox/action-gen-*；legacy 3 跳现页
- @qa: tests/test_t6_toolbox_e2e.py 5 用例真 pg + mock 网关零 token，无端点 bug
- P2 收尾: 限流→decisions.md 记延后(单用户原型)；noopener/Committable 早已修

守不变量 #2(只声明 tier)/#3(预览不写库,入库经验收 gate)/#9(缓存前缀)。无 DB 迁移。
门禁绿: 后端 ruff/format/mypy 195/alembic 无漂移/pytest 583；前端 lint/tsc/vitest 279/build。
spec 回写 PRODUCT_SPEC §7 + ARCHITECTURE §7.2 端点表。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ARCHITECTURE.md

@@ -785,6 +785,9 @@ def assemble(project_id, chapter_no):
 | POST | `/projects/:id/chapters/:no/refine` | `{段落, 指令}` | 回炉重写段(diff) | 200 |
 | GET | `/projects/:id/foreshadow` | `?status=` | 伏笔看板数据 | 200 |
 | POST | `/projects/:id/rules` | `{level, content}` | rule | 201 |
+| GET | `/skills/toolbox` | — | 生成器描述符列表(key/标题/input_fields/ingestable/legacy_route) | 200 |
+| POST | `/projects/:id/skills/:tool_key/generate` | `{brief, chapter_no?, count?, kind?}` | 结构化预览(不写库,仅记账) | 200 (未知 key 404/无 provider 503) |
+| POST | `/projects/:id/skills/:tool_key/ingest` | `{world_entities?\|scenes?, chapter_no?, acknowledge_conflicts}` | 入库结果 | 201 (continuity 冲突 409) |
 | GET/PUT | `/settings/providers` | 凭据/档位配置 | 配置(Key 脱敏) | 200 |
 | POST | `/settings/providers/test` | `{provider}` | 连接+能力矩阵 | 200 |