graph: integrate edge modifiers

[ruyadorno]

Add the ability for installs to use edge modifiers by using the "modifiers" to define an object containing keys that use a subset of the Dependency Selector Syntax and a spec value to override the current value in use, e.g:

  {
    "modifiers": {
      ":root > #eslint": "^8.0.0",
      "#react": "^16"
    }
  }

Refs: https://github.com/vltpkg/statusboard/issues/64

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Name	Status	Preview	Comments	Updated (UTC)
docs	⬜️ Ignored (Inspect)	Visit Preview		Jun 9, 2025 10:30pm

[Copilot]

Pull Request Overview

This PR integrates edge modifier functionality into the dependency graph, enabling installs to override current dependency values using a modifier query. Key changes include:

• Adding a new modifier property to Node and propagating modifier values through graph-building functions.
• Updating functions (install, addNodes, appendNodes, etc.) to load and apply a GraphModifier.
• Introducing a new check-nodes module that evaluates node modifications based on active modifiers.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/graph/src/node.ts	Adds a new "modifier" property to Node.
src/graph/src/install.ts	Loads GraphModifier and passes it to the build logic.
src/graph/src/ideal/get-importer-specs.ts	Extends importer specs options to include modifiers and tracks checks.
src/graph/src/ideal/check-nodes.ts	Introduces node checking for modifiers and triggers dependency appends.
src/graph/src/ideal/build.ts	Passes the modifiers option to the build process.
src/graph/src/ideal/build-ideal-from-starting-graph.ts	Integrates modifier checks into the graph build process.
src/graph/src/ideal/append-nodes.ts	Updates node appending logic to swap specs and update modifier entries.
src/graph/src/ideal/add-nodes.ts	Incorporates modifiers in the add-nodes workflow.
src/graph/src/graph.ts	Updates package placement to handle extra modifier information.
src/graph/src/actual/load.ts	Extracts modifier extra information from depID when loading manifests.

Comments suppressed due to low confidence (2)

src/graph/src/graph.ts:345

• [nitpick] Ensure that the semantics of the 'extra' parameter passed to getId are clearly documented, so downstream users understand how modifier information influences dependency identity.

const depId = id || (manifest && getId(spec, manifest, extra))

src/graph/src/actual/load.ts:289

• [nitpick] Consider adding a comment to explain the logic behind choosing between 'lastExtra' and 'maybeExtra', to clarify under which conditions each is used for modifier application.

extra = type === 'registry' || type === 'git' ? lastExtra : maybeExtra

[lukekarrys]

Code looks good and I built this PR locally and used it to install some simple modifiers which all worked!