Update imports in unloaded composite projects after file rename

[Copilot]

File renames only updated imports in already-loaded projects. Imports from unopened projects in the same composite project tree were omitted.

Changes

• Load the full project tree before collecting file-rename edits.
• Aggregate edits from newly loaded referenced projects.
• Add regression coverage for an unopened project importing the renamed file:

import { helper } from "../lib/helper";
// becomes
import { helper } from "../lib/renamed-helper";

[Copilot]

Pull request overview

Loads composite project trees before file-rename analysis so unopened dependent projects receive import updates.

Changes:

• Request full project-tree loading for rename operations.
• Add fourslash regression coverage.
• Add a project-state baseline confirming the dependent project loads.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/project/session.go	Loads project trees before creating language services.
internal/fourslash/tests/getEditsForFileRenameWithSolutionConfigFile_test.go	Verifies import updates in an unopened project.
testdata/baselines/reference/fourslash/state/getEditsForFileRenameLoadsUnopenedCompositeProject.baseline	Records expected project loading state.

[jakebailey]

Hm, doesn't this request this info for all callers now? Seems like a big hammer but maybe we should always have this info anyway?

I am not familiar enough apparently