view: show the values inside an include with bindings #2079

Found in the review of #2057, which adds the experimental view. It does not block that PR; #2059 fixed the findings that did. Paths refer to #2059's head.

Problem

An include with bindings evaluates a module with values other than its defaults:

// lib.gcl
param gain: Dimensionless = 1.0;
pub node out: Dimensionless = @gain;

// main.gcl
include review.lib(gain: 2.0) as p;
node y: Dimensionless = @p::out;

The view projects and caches models per module, so a pane for p could show only lib evaluated alone (out = 1), not the instance (out = 2). In #2057 such a pane showed 1 and wired it to y as the producer of 2.

PR #2059 added a stopgap. The view model's node instance is now { name, bound }. An include with bindings cannot be pinned, and no wires cross to it. So the reader cannot look inside such an instance at all.

Proposed fix

• Project a module alone and a concrete instance inside the root's evaluation as two kinds of target. This needs a Rust API that projects an instance from the root's evaluation, in graphcal-project, the language server and the Wasm engine.
• Give model requests, the model cache and pane keys a typed instance identity instead of a module id.
• Then allow pinning bound includes, with their own values and wires.