feat(plugins): add background document-indexer API (#1021)

Plugin API 1.2 gains an optional document-indexer export (plugin-indexing world). A plugin returns per document the keys it defines and refers to, aliases between key prefixes and gutter markers; the host indexes a trusted project in cancellable background batches, keeps the project-wide graph, and answers Go to Declaration / Ctrl-click and multi-target gutter markers from memory without calling the plugin again. Edits and file changes invalidate the affected entries; reload, disable or a failing runtime drops the plugin's graph.

The interface is limited to cross-file associations: icons chosen by file content and embedded-language regions are separate concerns for later interfaces. The plugin navigation choosers' titles are translated.

Co-authored-by: qjlqyf <[email protected]>

plugins/official/string-tools/dist/plugin.wasm.sources

@@ -1 +1 @@
-fa82a8596bd6505c769c0125ea26cef9af08535b36f650ddc4a353eb50866cea
+4fff5b261e8255aa2dac8342694dee129ea4a8c9520105c719d0c16a16846517