Move docs/ package mirror into document-navigator plugin

Relocate the ~6k-file docs tree from the repo root into
plugins/document-navigator/docs/ so the plugin is self-contained and
portable. docs/superpowers/ (specs and plans) stays at the repo root.

Moved via cp+rm rather than git mv because directory rename() fails with
EPERM on this WSL /mnt DrvFs mount; git rename-detection pairs the
identical-content files at commit time.

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

plugins/document-navigator/docs/api-stack/api/api-migrations/tests/integration/README.md

@@ -0,0 +1,29 @@
+# Integration tests — deferred
+
+The three dialect roundtrip tests (`sqlite`, `postgres`, `surrealql`) are
+deferred to a follow-up change. Justification:
+
+- **sqlite-wasm** requires a Web Worker and the WASM binary; running it under
+  vitest+Node in `forks` pool needs a non-trivial polyfill layer that does
+  not yet ship in `@suaveplan/testing` and would inflate this change beyond
+  scope. The `MemoryAdapter` in `src/runner/runner.test.ts` exercises the
+  full apply/select/insert/delete roundtrip against a real in-memory store
+  satisfying the same `MigrationAdapter` contract — every spec scenario is
+  covered.
+- **postgres** and **surrealql** roundtrips require Docker testcontainers
+  (`@suaveplan/testing-integration-postgres`, `-surrealdb`) which are
+  available but pull large images on every CI run. They will land in
+  `add-api-migrations-integration-tests` together with the sqlite-wasm worker
+  setup so the env requirements stay coherent.
+
+The shipped unit tests cover:
+
+- DDL emission per dialect (`src/adapters/<dialect>/<dialect>.test.ts`).
+- Row normalisation roundtrip per dialect.
+- Parameterised insert/delete per dialect.
+- Full apply / drift-detect / rollback flow via the in-memory `MemoryAdapter`
+  in `src/runner/runner.test.ts`.
+
+These do not stub crypto, fs, or the adapter contract — every test
+exercises the real `node:crypto` `createHash` and `node:fs/promises`
+`readdir`/`readFile`/`stat` calls.