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/persistence/database/db-sqlite/src/connection/connection.md

@@ -0,0 +1,83 @@
+# connection
+
+<!-- begin:auto-docs -->
+_(no submodules)_
+<!-- end:auto-docs -->
+## Purpose
+
+Provides thin singleton-management wrappers for `SqliteAdapter`, built on top of the `@suaveplan/db` singleton helpers. These functions let callers share a single connected `SqliteAdapter` instance across an application without manually tracking the singleton lifecycle or passing the adapter through every layer of the call stack.
+
+The helpers default the singleton name to `"default"` so simple applications need only call `getDefaultSqlite()` with no arguments. More complex applications with multiple databases use explicit names.
+
+## Features
+
+- `getDefaultSqlite(options?, config?, name?)` — creates-or-returns a connected `SqliteAdapter` singleton
+- `closeSqlite(name?)` — disconnects and removes the named singleton
+- `closeAllSqlite()` — disconnects and removes all `SqliteAdapter` singletons
+- `hasSqlite(name?)` — returns `true` if the named singleton exists and is connected
+- Default name: `"default"` — single-database apps never need to supply a name
+
+## Usage: Basic Example
+
+```ts
+import { getDefaultSqlite } from "@suaveplan/db-sqlite/connection/connection";
+
+const adapter = await getDefaultSqlite();
+const rows = await adapter.query("SELECT * FROM users");
+```
+
+## Usage: Advanced Example
+
+```ts
+import {
+  closeAllSqlite,
+  closeSqlite,
+  getDefaultSqlite,
+  hasSqlite,
+} from "@suaveplan/db-sqlite/connection/connection";
+
+// Primary database
+const primary = await getDefaultSqlite(
+  { filename: "/data/app.db" },
+  undefined,
+  "primary"
+);
+
+// Analytics read-only shard
+const analytics = await getDefaultSqlite(
+  { filename: "/data/analytics.db", readonly: true },
+  undefined,
+  "analytics"
+);
+
+console.log(hasSqlite("primary"));   // true
+console.log(hasSqlite("analytics")); // true
+
+await closeSqlite("analytics");
+console.log(hasSqlite("analytics")); // false
+
+// Shutdown — closes all remaining singletons
+await closeAllSqlite();
+```
+
+## API Reference
+
+### `getDefaultSqlite(options?, config?, name?): Promise<SqliteAdapter>`
+
+Creates a new `SqliteAdapter` using the given `options`, calls `connect(config)` on it, caches it under `name`, and returns it. Subsequent calls with the same `name` return the cached instance without reconnecting.
+
+### `closeSqlite(name?): Promise<void>`
+
+Disconnects and removes the singleton named `name`. No-op if no singleton by that name exists.
+
+### `closeAllSqlite(): Promise<void>`
+
+Disconnects and removes all singletons. Throws `AggregateError` if any disconnect fails.
+
+### `hasSqlite(name?): boolean`
+
+Returns `true` if a singleton exists under `name`.
+
+## Implementation Notes
+
+These functions delegate entirely to `@suaveplan/db`'s `getSingleton`, `closeSingleton`, `closeAllSingletons`, and `hasSingleton`. The `SqliteAdapter`-specific names (`getDefaultSqlite`, `closeSqlite`, etc.) exist for discoverability — callers working with SQLite need not know the generic singleton API. The return type is narrowed from `DatabaseAdapter` to `SqliteAdapter` via a cast so callers have access to SQLite-specific properties.