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/money/finance/currency-provider-ecb/src/ecb/ecb.md

@@ -0,0 +1,143 @@
+# EcbProvider
+
+<!-- begin:auto-docs -->
+_(no submodules)_
+<!-- end:auto-docs -->
+
+## Purpose
+
+`EcbProvider` is the `@suaveplan/currency` rate-source implementation for the
+European Central Bank's daily reference-rates XML feed. It is the lowest-
+friction fiat provider in the Suaveplan catalogue: free, no API key required,
+universal (runs in browsers, Web Workers, Node.js, and Bun), and built on
+the slim `@suaveplan/currency-providers` plugin core so every error path,
+abort-signal composition, and HTTP wrapping is shared with every other sibling
+provider in the family.
+
+The package exposes a single class, `EcbProvider`, with stable identity flags
+(`name === "ecb"`, `supportsFiat === true`, `supportsCrypto === false`). It is
+not auto-registered with any registry — consumers wire it through either
+`new CurrencyConverter({ provider: new EcbProvider() })` or
+`registry.register(new EcbProvider())` against a
+`CurrencyProviderRegistry` from `@suaveplan/currency-providers`.
+
+## Features
+
+- Free, no authentication — public ECB daily XML feed.
+- ~30 fiat currencies (every major plus many minor European / global pairs).
+- Updates around 16:00 CET each business day; weekends and bank holidays
+  return the last published snapshot.
+- Default base is EUR; any non-EUR base is synthesised by inverting through
+  the EUR rates so callers never have to triangulate manually.
+- Optional `targets` filter so consumers iterating a small basket avoid
+  caching the full 30-currency table.
+- Typed `CurrencyProviderError` on every failure path: `HTTP_ERROR` for non-
+  2xx upstream responses, `PARSE_ERROR` for an unparseable body,
+  `UNSUPPORTED_BASE` when the requested base is missing from the EUR-quoted
+  table, `UNKNOWN_CURRENCY` when every requested target is absent.
+- `AbortSignal` propagation — `RateFetchOptions.signal` is forwarded through
+  the slim core's `httpRequest()` so callers can cancel in-flight requests.
+- Injectable `FetchLike` (from `@suaveplan/types`) — tests pass a recording
+  closure; production accepts the default `globalThis.fetch`.
+- Zero runtime dependencies beyond `@suaveplan/currency-providers` /
+  `@suaveplan/currency` / `@suaveplan/types` / `tslib`.
+
+## Usage
+
+### Basic Example
+
+```ts
+import { CurrencyConverter } from "@suaveplan/currency";
+import { EcbProvider } from "@suaveplan/currency-provider-ecb";
+
+const converter = new CurrencyConverter({
+    provider: new EcbProvider(),
+});
+
+const rate = await converter.getRate("EUR", "USD");
+console.log(`1 EUR = ${rate} USD`);
+```
+
+### Advanced Example
+
+Wiring through the slim core's registry with a custom `baseUrl` (e.g. an
+internal proxy that caches the upstream XML at the edge) and a caller-side
+`AbortSignal` so a UI cancellation aborts the in-flight HTTP request.
+
+```ts
+import { CurrencyConverter } from "@suaveplan/currency";
+import { CurrencyProviderRegistry } from "@suaveplan/currency-providers";
+import { EcbProvider } from "@suaveplan/currency-provider-ecb";
+
+const registry = new CurrencyProviderRegistry();
+registry.register(
+    new EcbProvider({
+        baseUrl: "https://cdn.internal.example.com/ecb/daily.xml",
+    }),
+);
+
+const controller = new AbortController();
+setTimeout(() => controller.abort(new Error("user navigated away")), 5_000);
+
+const provider = registry.get("ecb");
+const result = await provider.fetchRates({
+    base: "USD",
+    targets: ["EUR", "GBP", "JPY"],
+    signal: controller.signal,
+});
+
+console.log(result.base, result.rates, result.timestamp);
+```
+
+## API Reference
+
+### `class EcbProvider implements CurrencyProvider`
+
+#### `constructor(config?: NoKeyConfig)`
+
+- `config.baseUrl?: string` — override the default ECB endpoint
+  (`https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml`).
+- `config.fetch?: FetchLike` — injectable `fetch` implementation; defaults to
+  `globalThis.fetch` resolved at call time.
+
+#### Read-only fields
+
+- `name: "ecb"` — stable identifier surfaced as `CurrencyProvider.name`.
+- `supportsFiat: true`
+- `supportsCrypto: false`
+
+#### `fetchRates(options?: RateFetchOptions): Promise<RateFetchResult>`
+
+Fetches and returns the latest ECB rates. `options.base` defaults to `"EUR"`;
+when set to any other currency the result is synthesised by inverting through
+the EUR-quoted feed. `options.targets` filters the returned map.
+`options.signal` is forwarded to the underlying HTTP call.
+
+**Throws** `CurrencyProviderError` with one of:
+
+- `HTTP_ERROR` — non-2xx response (raised by the slim core's `httpRequest`).
+- `PARSE_ERROR` — response body contained no parseable currency tags.
+- `UNSUPPORTED_BASE` — caller asked for a non-EUR base that is not in the
+  EUR-quoted feed.
+- `UNKNOWN_CURRENCY` — every entry in `options.targets` was absent from the
+  resolved rate map.
+
+## Implementation Notes
+
+- The ECB endpoint always publishes EUR-based rates. Non-EUR bases are
+  derived purely arithmetically — there is no second HTTP call. This is
+  the same algorithm the upstream `@suaveplan/currency-providers` shipped
+  before the 2026-05-17 slim refactor split it into siblings.
+- XML parsing uses a regex (`currency='([A-Z]+)'\s+rate='([\d.]+)'`) rather
+  than a full XML parser to keep the package zero-runtime-dep beyond the
+  slim core and `@suaveplan/currency`. The ECB feed shape is stable; if the
+  upstream format changes, the failure surfaces immediately as
+  `PARSE_ERROR`.
+- Rates are not available on weekends or ECB bank holidays; the feed returns
+  the last published snapshot. Consumers that need same-day freshness should
+  layer `@suaveplan/currency`'s `staleDurationMs` on top.
+- `globalThis.fetch` is resolved at call time, not constructor time, so test
+  setups that replace the global between construction and the first
+  `fetchRates()` call still work.
+- The package declares `"sideEffects": false` and ships explicit named barrels
+  per AGENTS.md §6a; tree-shaking unused exports is safe.