Handle unloaded projects in API snapshot responses

[ulitink]

Opening a file can load its nearest configured project while solution search discovers an ancestor tsconfig as an unloaded placeholder. API updateSnapshot previously serialized every project assuming CommandLine was non-nil, which couldp anic for that unloaded ancestor project.

Error: panic: runtime error: invalid memory address or nil pointer dereference
goroutine 932 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:26 +0x5e
github.com/microsoft/typescript-go/internal/api.(*AsyncConn).handleRequest.func1()
	github.com/microsoft/typescript-go/internal/api/conn_async.go:96 +0x58
panic({0xdd6c80?, 0x1b43150?})
	runtime/panic.go:860 +0x13a
github.com/microsoft/typescript-go/internal/tsoptions.(*ParsedCommandLine).FileNames(...)
	github.com/microsoft/typescript-go/internal/tsoptions/parsedcommandline.go:295
github.com/microsoft/typescript-go/internal/api.NewProjectResponse(...)
	github.com/microsoft/typescript-go/internal/api/proto.go:500
github.com/microsoft/typescript-go/internal/api.(*Session).handleUpdateSnapshot(0x18b1c3e22230, {0x11cec30, 0x18b1c3f85950}, 0x18b1bd2e5dc0)
	github.com/microsoft/typescript-go/internal/api/session.go:913 +0x1401
github.com/microsoft/typescript-go/internal/api.(*Session).HandleRequest(0x18b1c3e22230, {0x11cec30, 0x18b1c3f85950}, {0x18b1bc646902, 0xe}, {0x18b1b97a2980?, 0x18b1bbdca708?, 0x18b1c1549790?})
	github.com/microsoft/typescript-go/internal/api/session.go:521 +0xbe9
github.com/microsoft/typescript-go/internal/api.(*AsyncConn).handleRequest(0x18b1c3f859a0, {0x11cec30?, 0x18b1c3f85950?}, 0x18b1c35761e0)
	github.com/microsoft/typescript-go/internal/api/conn_async.go:112 +0xb4
created by github.com/microsoft/typescript-go/internal/api.(*AsyncConn).Run in goroutine 899
	github.com/microsoft/typescript-go/internal/api/conn_async.go:66 +0x105

[ulitink]

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[Copilot]

Pull request overview

This PR addresses a panic in the API updateSnapshot response serialization path when a snapshot contains an “unloaded” configured project whose CommandLine is nil (e.g., an ancestor tsconfig discovered during solution search).

Changes:

• Add a regression test covering serialization of a snapshot that includes both a loaded nested configured project and an unloaded ancestor configured project.
• Update NewProjectResponse to avoid dereferencing p.CommandLine when it is nil.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
internal/api/proto.go	Adds a nil guard in NewProjectResponse to prevent panics when serializing projects without a command line.
internal/api/session_apistate_test.go	Adds a regression test that exercises updateSnapshot when an unloaded ancestor configured project is present.

[andrewbranch]

Can we just filter these stub projects out of the API response instead?