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/testkit/testing/testing-integration-postgres/README.md

@@ -0,0 +1,43 @@
+# @suaveplan/testing-integration-postgres - PostgreSQL 16 testcontainers fixture for @suaveplan/testing-integration
+
+## Summary
+
+PostgreSQL 16 testcontainers fixture for `@suaveplan/testing-integration`.
+
+Implements `ServiceFixture<PostgresConfig>` — manages a PostgreSQL container lifecycle with env-bridge passthrough and `pg_isready` health checks. Returns a plain config; consumers bring their own `pg` client.
+
+<!-- begin:auto-docs -->
+## Documentation tree
+
+- [fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_ <!-- end:auto-docs -->
+  - [postgres-fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_ <!-- end:auto-docs -->
+<!-- end:auto-docs -->  - [postgres-fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_- [postgres-fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_- [postgres-fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_- [postgres-fixture](./src/fixture/postgres-fixture.md) — <!-- begin:auto-docs --> _(no submodules)_
+## Install
+
+```bash
+bun add -D @suaveplan/testing-integration-postgres
+```
+
+## Quick Start
+
+```typescript
+import { PostgresFixture } from "@suaveplan/testing-integration-postgres";
+
+const fixture = new PostgresFixture();
+const config = await fixture.start();
+// config.url, config.host, config.port, config.database, config.username, config.password
+await fixture.stop();
+```
+
+## Env-bridge passthrough
+
+Set the env var to skip container startup:
+
+```text
+POSTGRES_URL=postgresql://test:test@localhost:5432/test
+```
+
+## Docs
+
+- [PostgresFixture](src/fixture/postgres-fixture.md)
+