[api] Fix named pipe / UDS creation

[Andrew Branch (andrewbranch)]

One semi-related fix per commit.

• af47f84: when creating a UDS for an API client, create a tmp directory first and set permissions on the socket path to 0o600
• 058a1ed: when an LSP client asks for an API socket to be created by a specific name, interpret that as the name of the tmp directory to be created and make the socket path ${tmpdir}/socket, so the same strategy as above can be used
• 416b013: use a random pipe name on Windows when spawning the sync API

[Copilot]

🟡 Changes recommended

Repeated transport closure can delete a replacement Unix socket and prevent new connections.

1 open finding

• Prevent repeated cleanup from deleting replacement Unix socket · New

What changed in this PR

Improves API transport creation for the native TypeScript compiler and language server.

Changes:

• Creates private Unix socket directories with explicit permissions and cleanup.
• Updates explicit Unix path semantics and documentation.
• Randomizes Windows sync API pipe names.

File	Description
tsc/​internal/​lsp/​server.go	Creates private transports and returns their actual paths.
tsc/​internal/​lsp/​lsproto/​lsp_generated.go	Documents Unix directory semantics.
tsc/​internal/​ipc/​transport.go	Adds private transport creation and cleanup.
tsc/​internal/​ipc/​transport_windows.go	Adapts Windows listener creation.
tsc/​internal/​ipc/​transport_unix.go	Creates permission-restricted sockets and directories.
tsc/​internal/​ipc/​transport_unix_test.go	Tests permissions, directory reuse rejection, and cleanup.
tsc/​internal/​api/​server.go	Updates pipe option documentation.
tsc/​cmd/​tsc/​api.go	Updates command-line pipe help.
tools/​scripts/​lsp/​generate.mts	Updates protocol documentation generation.
packages/​typescript/​src/​api/​syncChannel.ts	Uses randomized Windows pipe names.

Files not reviewed (1)

• tsc/internal/lsp/lsproto/lsp_generated.go: Generated file

🧠 Review effort: Balanced

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[Copilot]

🟡 Changes recommended

The Windows connectivity test lacks an Accept call, causing dialing to time out despite correct permissions.

1 open finding

• Start pipe Accept before DialPipe in Windows test · New

1 resolved since last review

• Prevent repeated cleanup from deleting replacement Unix socket

Files not reviewed (1)

• tsc/internal/lsp/lsproto/lsp_generated.go: Generated file

🧠 Review effort: Balanced

[Copilot]

🔵 Needs a closer look

Cross-platform access controls and cleanup behavior need Unix and Windows validation that was not performed during this review.

0 open findings

1 resolved since last review

• Start pipe Accept before DialPipe in Windows test

Files not reviewed (1)

• tsc/internal/lsp/lsproto/lsp_generated.go: Generated file

🧠 Review effort: Balanced

[Jake Bailey (jakebailey)]

After this is merged, see if we can do a cherry pick of this to release-7.0 (the bot won't let you do it until this is merged, but I bet it conflicts anyway)

[Andrew Branch (andrewbranch)]

TypeScript Bot (@typescript-bot) cherry-pick this to release-7.0

[typescript-automation]

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
cherry-pick this to release-7.0	✅ Started	❌ Results

[typescript-automation]

Hey, Andrew Branch (@andrewbranch)! I was unable to cherry-pick this PR.

Check the logs at: https://github.com/microsoft/TypeScript/actions/runs/38650096582