A workflow hierarchy is read from one cached export, and navigated from an outline

[endrix]

Phase 5 of docs/proposals/single-editor-hierarchy.md. The runtime side is huawei-csl/wfpy#45 (wfpy plan --format graph --hierarchy).

Navigating a hierarchy in one editor ran the runtime's plan for every view you drilled into. That was a process per level, and each nested workflow was elaborated standalone rather than as its parent's instance. The only way down was one double-click per level.

One cached export per root

• A product that can export a whole hierarchy supplies cliHierarchyArgs(file, rootWorkflow).
• CliGraphModelSource.viewFromHierarchy then reads every view, root or nested, from one export per root. The root comes from the trail's first crumb; the view is the instance at the trail's instance path.
• HierarchyCache keeps an export while every file it came from (the root's and each nested definition's) has the same content hash, and exports again once any changes.
• Fallbacks to a plan of its own: an instance that did not elaborate, a trail that does not line up, or unsaved text being previewed.

The outline, modelled on mlir-viewer's

• The export's tree, without graphs (outlineOf), reaches the root model as wf:hierarchy (new GraphDocument.hierarchy / HierarchyOutlineEntry in shared).
• HierarchyOutlinePanel is a model-root listener, shown only when navigating in place and a hierarchy is present.
  • toggle button and O;
  • filter that keeps the ancestors of a match;
  • rows with instance name, workflow, a chip for a file other than the root's, node and nested counts, and error or truncated markers;
  • single click selects and centers the instance in the view containing it, opening that view first if needed;
  • double click opens its view at the trail a drill-down would give;
  • the current view's row is highlighted and its ancestors opened.
• The pure helpers live in hierarchy-outline-tree.ts, tested headlessly.

Not yet: a run's state (running / done / failed) on the rows.

Container parity: the baseline gains exactly the panel's two bindings (self, and as an IGModelRootListener). I diffed the composition before accepting them.

Tests: hierarchy cache and view reading (8), outline helpers and node lookup (8), wf:hierarchy on the root (2). I also checked the shape of a real wfpy plan --hierarchy export against what the cache reads. All workspaces pass, with neutrality 5/5 and typecheck 5/5.

wfpy-ide supplies cliHierarchyArgs in a separate PR.

https://claude.ai/code/session_015VK7fH1c4aKbexnq2QcuKU