arcrun — AI workflow execution engine (clean history)

Self-hosted 開源：WASM 零件 + recipe + cypher-executor，跑在你自己的 Cloudflare。

此為重建的乾淨歷史起點（移除曾誤 commit 的 GCP SA 金鑰，舊歷史保留在
richblack/arcrun 與本地 backup 分支）。含：
- acr init --self-hosted installer（建 KV/R2 + codeload 拉預編譯 wasm + wrangler deploy + seed recipe）
- recipe push 把關（資料外流提醒 + 打通檢查）
- 19 個正當零件預編譯 wasm（claude_api/km_writer/kbdb_upsert_block 排除：違反 DECISIONS §1）
- CLI / cypher-executor / registry / 完整 SDD

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

registry/components/km_writer/component.contract.yaml

@@ -0,0 +1,67 @@
+canonical_id: "km_writer"
+display_name: "KM Writer"
+category: "api"
+version: "v1"
+wasi_target: "preview1"
+stability: "floating"
+runtime_compat:
+  - "cf-workers"
+  - "workerd"
+constraints:
+  max_size_kb: 2048
+  max_cold_start_ms: 50
+  no_network_syscall: false
+  no_filesystem_syscall: true
+  io_model: "stdin_stdout_json"
+input_schema:
+  type: object
+  required: [action, mira_url, token]
+  properties:
+    action:
+      type: string
+      description: "操作類型：read_journal | read_journal_date | append_journal | list_pages | read_page | write_page"
+      enum: [read_journal, read_journal_date, append_journal, list_pages, read_page, write_page]
+    mira_url:
+      type: string
+      description: "Mira 服務基礎 URL（例：https://mira.uncle6.me）"
+    token:
+      type: string
+      description: "Mira MIRA_TOKEN（Bearer token）"
+    content:
+      type: string
+      description: "內容（append_journal / write_page 時必填）"
+    timestamp:
+      type: string
+      description: "ISO 8601 時間戳（append_journal 時選填，影響日期和時間顯示）"
+    date:
+      type: string
+      description: "日期 YYYY-MM-DD（read_journal_date 時必填）"
+    name:
+      type: string
+      description: "頁面名稱（read_page / write_page 時必填）"
+output_schema:
+  type: object
+  properties:
+    success:
+      type: boolean
+    data:
+      type: object
+      description: "Mira API 回應資料"
+    error:
+      type: string
+      description: "錯誤訊息（success=false 時）"
+gherkin_tests:
+  - scenario: "缺少 action"
+    given: '{"mira_url":"https://mira.uncle6.me","token":"abc"}'
+    then_contains: '{"success":false'
+  - scenario: "缺少 token"
+    given: '{"action":"list_pages","mira_url":"https://mira.uncle6.me"}'
+    then_contains: '{"success":false'
+tags: [km, journal, logseq, mira, knowledge-management]
+description: "讀寫 Mira leo-graph 的 journals 和 pages。透過 host function 呼叫 Mira /km/* API，支援讀取、新增日誌條目，以及讀寫頁面。"
+config_example: |
+  append_to_journal:
+    action: "append_journal"
+    mira_url: "https://mira.uncle6.me"
+    token: "<mira_token>"
+    content: "今天完成了 arcrun km_writer 元件"