feat: sync and reference Very Good Engineering content

[ryzizub]

What

Pull the latest published FFCA standard from Very Good Engineering at session start, and have skills and the auditor read that cache instead of the bundled copy in references/ffca_architecture.md.

Why

references/ffca_architecture.md is a hand-maintained mirror of the FFCA page, and scripts/sync_reference.dart is still a stub. Every change to the standard needs a manual edit plus a plugin release, and plugins are not updated reliably on local machines. The mirror drifts as soon as the source changes. Same approach as VeryGoodOpenSource/vgv-ai-flutter-plugin#158.

How

• A SessionStart hook runs a sync script before any work begins.
• The script compares the locally cached VGE version against the published one.
• Minor difference: download and overwrite the cache.
• Major difference: keep the cached copy and wait for a plugin release, since renamed or new sections may need skills rewired. Skills cite sections by name, such as Dependency Graph Rules and Naming Conventions (Enforced).
• The cache lives outside the plugin directory so it survives reinstalls.
• The bundled references/ffca_architecture.md stays as the fallback when no cache exists.

Sync must fail open. A network failure, a slow response, or an offline machine cannot block the session or the hook's time budget.

Sections

FFCA architecture. Layered Architecture too, since the skills defer to it for non-FFCA repos.

Tasks

• Add the sync script and wire it to SessionStart in hooks/hooks.json
• Pin the VGE version this plugin was built against
• Hold on a major difference, sync on a minor one
• Fail open on any network or parse error
• Point skills and ffca-layer-auditor at the cache, falling back to the bundled reference
• Replace or remove the scripts/sync_reference.dart stub
• Check whether validate_layers.dart rules need to follow the synced standard

Blocked

Waiting on Very Good Engineering to publish FFCA and to ship versioned, downloadable bundles. Nothing here is implementable until that lands.