docs(architecture): 用现行单一提供者事实取代指向已删除 ADR-0001 的死链 (#6733) (#6869)

`ARCHITECTURE.md` 的 ADR 小节指向 `docs/adr/0001-metadata-service-architecture.md`,
该文件已于 2026-02-11 在 `9da8e3e72` 中随 ADR-0002 与 `docs/adr/README.md` 一并删除,
读者点进去是 404。

不做「换个 ADR 重指」的机械修复:该链接承载的论断——「ObjectQL 与 MetadataPlugin
都可以提供 metadata 服务,MetadataPlugin 优先、ObjectQL 兜底」——本身已经不成立。
按 origin/main 核对:

- `packages/metadata/src/plugin.ts` 是唯一 `registerService('metadata', …)` 的地方;
  `packages/objectql/src/plugin.ts` 只注册 `objectql` / `data` / `manifest` / `lifecycle`,
  没有 `metadata`。
- ObjectQL 已退为消费者:`start()` 里读 metadata 服务、同步定义、订阅事件,
  取不到时退回自身内部 registry。
- ADR-0001 幸存的那一半(共享接口)如今是 spec 契约
  `packages/spec/src/contracts/metadata-service.ts` 的 `IMetadataService`,
  槽位声明在 `packages/spec/src/system/core-services.zod.ts`。

因此该小节改为:以纯文本(非链接)记下被删路径与删除出处,陈述现行单一提供者架构并
指向上述活的契约与实现文件,仓储/变更日志/订阅机制指向仍在的 ADR-0008。并明确写出
「单一提供者这个决策目前没有 ADR 归属」——重新立档是维护者的事(PD #14),本 PR 不碰
`docs/adr/**`。

顺带把 `scripts/check-adr-anchors.mjs` 中 `UNRESOLVED_ADR_CITATIONS` 的 `0001` 条注释
更新为事实:它原本写「ARCHITECTURE.md still carries a markdown LINK」,本 PR 之后这句
不再为真。条目本身保留——ADR-0002 的历史引用仍让它 earning its place,门禁的 stale 检查
已验证(绿)。


Claude-Session: https://claude.ai/code/session_01F8q5J1MQyocgtNspb15fSn

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-project-manager

ARCHITECTURE.md

@@ -648,9 +648,31 @@ export type Field = z.infer<typeof FieldSchema>;
 
 ### Architecture Decision Records (ADRs)
 
-Important architectural decisions are documented as ADRs in `docs/adr/`:
-
-- [ADR-0001: Metadata Service Architecture](docs/adr/0001-metadata-service-architecture.md) - Explains why both ObjectQL and MetadataPlugin can provide metadata service and how they work together
+Important architectural decisions are documented as ADRs in `docs/adr/`.
+
+**Metadata service architecture.** This section used to link
+`docs/adr/0001-metadata-service-architecture.md`, deleted on 2026-02-11 in `9da8e3e72`
+(together with ADR-0002 and the ADR `README.md`). The link is deliberately not repointed
+at another record, because the decision it carried — *both ObjectQL and MetadataPlugin can
+provide the metadata service, MetadataPlugin taking precedence and ObjectQL acting as
+fallback* — is no longer what the code does. Today:
+
+- **MetadataPlugin is the sole provider** of the `metadata` service
+  (`packages/metadata/src/plugin.ts`). `ObjectQLPlugin` registers `objectql`, `data`,
+  `manifest` and `lifecycle` — never `metadata`.
+- **ObjectQL is a consumer.** In `start()` it reads the `metadata` service, syncs
+  definitions into its own registry and subscribes to metadata events, and degrades to
+  that internal registry when no such service is present
+  (`packages/objectql/src/plugin.ts`).
+- **The shared-interface principle survived, as a spec contract**: `IMetadataService` in
+  `packages/spec/src/contracts/metadata-service.ts`, with the slot declared as
+  `CoreServiceName 'metadata'` in `packages/spec/src/system/core-services.zod.ts`.
+- **Repository, change-log and subscription mechanics** are recorded in
+  [ADR-0008: Metadata Repository, Change Log & Subscription](docs/adr/0008-metadata-repository-and-change-log.md).
+
+The single-provider decision itself has **no ADR record today** — ADR-0001 was deleted and
+nothing replaced it. Re-homing it is a maintainer call; until then the contract and the two
+plugin files above are the live source of truth.
 
 ### Component-Specific Documentation
 

scripts/check-adr-anchors.mjs

@@ -193,10 +193,13 @@ const UNRESOLVED_ADR_CITATIONS = [
     // Deleted 2026-02-11 (9da8e3e72) together with 0002-database-driven-metadata-
     // storage.md and docs/adr/README.md, in the permission-protocol rewrite.
     // Cited as history by `docs/adr/0002-...md` ("already discarded in v3.4's
-    // ADR-0001"). ⚠️ ARCHITECTURE.md still carries a markdown LINK to the deleted
-    // path — a genuinely broken pointer, not history, filed separately from
-    // #6634; this entry keeps the gate honest about the number, it does not
-    // bless that link.
+    // ADR-0001"), which is what keeps this entry earning its place.
+    // ARCHITECTURE.md used to carry a markdown LINK to the deleted path — a
+    // genuinely broken pointer rather than history, filed separately from #6634
+    // and fixed in #6733: that section now names the deleted path as plain text
+    // and states the current single-provider architecture (MetadataPlugin is the
+    // sole `metadata` provider; ObjectQL consumes it) instead of pointing at a
+    // 404. This entry never blessed that link and does not bless any future one.
     why: 'record deleted 2026-02-11 (9da8e3e72); cited as history by ADR-0002',
   },
   {