feat(plugins): add Anki card-mined event, AnkiConnect invoke, anki-sync

- Add ctx.anki.on('card-mined') fed by polling, proxy, and card creation once enrichment finishes
- Add ctx.anki.invoke to send one AnkiConnect action to the effective url with no retries
- Ship example anki-sync plugin that syncs to AnkiWeb after mining goes quiet or playback ends
- Unload plugins that finish activating after unloadAll gave up on them
- Document the Anki API and anki-sync plugin in docs-site and architecture docs

assets/plugins/anki-sync/main.js

@@ -0,0 +1,61 @@
+// Runs AnkiConnect's `sync` (AnkiWeb) after you mine cards. A burst of mining becomes one sync:
+// it waits until no card has been mined for `delayMs`, and syncs right away when playback ends.
+// Also registers a `sync` action for a manual sync.
+
+const DEFAULT_SETTINGS = {
+  delayMs: 30_000,
+  syncOnEnd: true,
+  timeoutMs: 60_000,
+  notify: true,
+};
+
+const END_REASONS = new Set(['eof', 'stop', 'quit']);
+
+function activate(ctx) {
+  const settings = { ...DEFAULT_SETTINGS, ...ctx.settings };
+  // Cards mined since the last sync started.
+  let dirty = false;
+  let syncing = false;
+  let cancelTimer = null;
+
+  function schedule() {
+    cancelTimer?.();
+    cancelTimer = ctx.after(settings.delayMs, flush);
+  }
+
+  async function flush() {
+    cancelTimer?.();
+    cancelTimer = null;
+    // A sync already running picks up new cards when it finishes.
+    if (!dirty || syncing) return;
+    dirty = false;
+    syncing = true;
+    try {
+      await ctx.anki.invoke('sync', {}, { timeoutMs: settings.timeoutMs });
+      ctx.log.info('Synced Anki.');
+      if (settings.notify) ctx.notify('Anki synced');
+    } catch (error) {
+      ctx.log.warn(`Anki sync failed: ${error.message}`);
+      ctx.notify(`Anki sync failed: ${error.message}`, { variant: 'error' });
+    } finally {
+      syncing = false;
+      if (dirty) schedule();
+    }
+  }
+
+  ctx.anki.on('card-mined', () => {
+    dirty = true;
+    schedule();
+  });
+
+  ctx.mpv.on('end-file', ({ reason }) => {
+    if (settings.syncOnEnd && END_REASONS.has(reason)) return flush();
+  });
+
+  ctx.actions.register('sync', () => {
+    dirty = true;
+    return flush();
+  });
+}
+
+module.exports = { activate };

assets/plugins/anki-sync/plugin.json

@@ -0,0 +1,5 @@
+{
+  "name": "Anki Sync",
+  "version": "1.0.0",
+  "main": "main.js"
+}