feat(定时任务): 内置「模板数据转换器」按 HTML 模板填充 JSON 生成大屏

- 模板填充引擎 template_fill.py：模板注册表 + schema 骨架 + 结构校验 + 行级安全填充；
  模板自带 DATA 即 schema 来源。no.1 可转换填充（含 MANIFEST 更新时间刷新），
  no.2 暂为「只展示」(convertible=False) 原样输出已有数据
- 内置 agent template-json-builder（seed + SOUL），随 lifespan 注入，自动出现在
  定时任务「执行智能体」下拉
- 调度器新增模板填充执行分支 _run_template_fill_attempt：源 JSON→大模型转换→
  结构校验→失败回喂重试；空源/只展示模板直接用模板默认数据，绝不失败
- API：GET /api/scheduled-tasks/html-templates
- 前端：选中该 agent 后条件渲染「HTML模板」下拉 + .json 上传，只展示型模板隐藏 JSON 输入
- 文档同步（前后端 CLAUDE.md）

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

offline-backend-20260512/backend/CLAUDE.md

@@ -300,6 +300,8 @@ Two on-demand/automatic refresh paths layer on top:
 
 **Unified output switches (`require_html` + `require_markdown`).** The task form no longer splits "???? / HTML ??" into separate kinds. `execution_context` now carries two **independent** booleans that may both be on: `require_html` (???? HTML) and `require_markdown` (???? Markdown). `_task_requires_html()` returns true for `require_html` **or** legacy `task_kind == "html_page"` (so old tasks need no data migration), and `_run_task_attempt()` dispatches to `_run_html_page_attempt` when it is true, else the regular agent attempt. When **both** switches are on, `_gather_html_data()` returns `(text, files)` ? the gather agent run is additionally told to save a `.md` file ? and `_run_html_page_attempt` validates it (`MarkdownRequirementError` on failure) and surfaces it alongside the generated page, so the run delivers both artifacts. The single main `prompt` doubles as the HTML page requirement (`html_config.page_prompt`); there is no separate page-prompt field. Tests: `tests/test_scheduled_task_require_html.py` + the markdown-coexistence cases in `tests/test_html_page_tasks.py`.
 
+**Template-fill mode (JSON → 固定 HTML 模板填充).** A third execution mode, distinct from the free-form `require_html` render pipeline: convert a user-supplied JSON into a **fixed** HTML template's data structure and fill it. Triggered when `execution_context.template_config.template_id` is set (chosen in the task form after selecting the built-in **「模板数据转换器」** agent `template-json-builder`). `_task_template_id()` reads it and `_run_task_attempt()` dispatches to `_run_template_fill_attempt` **before** the `require_html` check. Pipeline: take source JSON (the task `prompt`, pasted or uploaded .json) → load the selected agent's `SOUL.md`+model and run a **direct** `_invoke_conversion_model` call (system=SOUL, human=conversion prompt carrying the template's compact **schema skeleton** + source) → `extract_json_object` → `template_fill.validate_data` (top-level keys + container types) → **on failure feed the structure errors + `field_coverage_gaps` back and retry up to `_MAX_TEMPLATE_FILL_RETRIES`=2** → `template_fill.fill_template` replaces the template's `const DATA={…}` line (and refreshes `MANIFEST.系统.更新时间`) → archive `index.html` + persist a `scheduled_html_pages` row → return `format:"html"` (reusing the existing HTML preview at `/runs/{id}/html`). Any terminal failure raises `TemplateFillError` → run marked failed (no retry, message shown). **Pure engine** `deerflow/runtime/scheduler/template_fill.py` (harness, no `app.*`): the template registry (`TEMPLATES`: id=`no1` name=`no.1` 台湾滨海防卫大屏, and id=`no2` name=`no.2` 台湾飞行部队平台 with **`convertible=False`** — a 「只展示」 template that renders its existing HTML **as-is**, no model/validation/fill, until conversion is wired in later; `_run_template_fill_attempt` short-circuits to `read_template_text` for it, and `list_templates`/`is_convertible` expose the flag so the form hides the JSON input), `list_templates`/`reference_data`/`schema_skeleton_json`/`validate_data`/`field_coverage_gaps`/`fill_template` — **the template's own embedded `DATA` is the schema source of truth** (parsed at load, 1-sample-per-array skeleton fed to the LLM, top-level structure as the validation basis); template HTML files live under `runtime/scheduler/templates/<id>/`, add a `TemplateSpec` to register a no.2. The agent is seeded like the AI-writing ones: `app/gateway/routers/_template_builder_seed.py` + `_template_builder_seed_assets/template-json-builder/{config.yaml,SOUL.md}`, called from the lifespan before `_sync_legacy_agents` (which upserts it into the `agents` table as built-in/published so it shows in `/api/agents` → the task form's 执行智能体 dropdown). Template list API: `GET /api/scheduled-tasks/html-templates` → `{templates:[{id,name,description}]}` (open). Frontend: when the agent dropdown = `template-json-builder` the form hides the HTML/Markdown switches and shows a 「HTML模板」 select (`useHtmlTemplates`) + a .json upload (reads file text into the prompt box). Tests: `tests/test_template_fill.py`, `tests/test_template_fill_attempt.py`, `tests/test_template_builder_seed.py`.
+
 ### Per-user Prompts & UI Preferences
 
 **Custom prompts can be scoped to one agent.** `user_custom_prompts` gains a nullable `agent_id` column (migration `20260603_02`): `NULL` = global (the chip shows in every chat), otherwise the prompt only surfaces when that agent is selected. The visibility filter is applied in the frontend `CustomPromptBar` (it receives the current agent id from `ChatPage`'s selector or `AgentChatPage`'s `assistantId`); the backend (`/api/user-prompts` CRUD) just stores/returns/clears `agent_id` (update accepts an explicit `null` to clear). Tests: `tests/test_user_prompts_agent_id.py`.