fix: harden process matching during updates

[Dmitriy Vasyura (dmitrivMS)]

Summary

• resolve candidate processes by launch name and installation directory before waiting or requesting termination rights
• use QueryFullProcessImageNameW with limited query access so the 32-bit updater can inspect 64-bit processes
• hold process handles across the wait to prevent PID reuse and access-denied polling races
• correctly check TerminateProcess failures and wait for confirmed process exit
• cover same-name processes in other installations and the Code.exe to old_Code.exe rename flow

Issue

Fixes microsoft/vscode#76641.

Supersedes #28

This supersedes #28, which ignores ERROR_ACCESS_DENIED after requesting query and termination rights before establishing whether a same-named process belongs to this installation. That approach can still wait on every Code.exe from other users for 30 seconds, and it can hide a real termination failure for the target installation.

This PR instead queries process identity first with PROCESS_QUERY_LIMITED_INFORMATION, filters by the executable's launch name and installation directory, and only requests termination rights for verified targets. It also uses a cross-bitness-safe path API and preserves actionable termination errors.

The launch-name plus directory match is intentional: Windows updates the image path after Code.exe is renamed to old_Code.exe, while Toolhelp preserves the original launch name.

Related issues

This may also help variants reported in:

• Orphaned crashpad-handler child process survives update and pegs a CPU core indefinitely (Windows) vscode#320573
• Windows update failed: Access is denied vscode#47841
• Can't Install local user update due to \\bin folder being used by another process vscode#60697

Validation

• cargo check --target i686-pc-windows-msvc
• cargo test --target i686-pc-windows-msvc (23 passed)
• process tests run from the i686 updater test binary against an x64 helper, covering the cross-bitness path

[Copilot]

Pull request overview

This PR hardens Windows process detection and termination in the updater by identifying candidate processes using both launch name and installation directory, using a cross-bitness-safe image path query, and holding process handles to avoid PID-reuse races.

Changes:

• Introduces handle-owned process matching (launch name + install directory) using QueryFullProcessImageNameW and case-insensitive ordinal comparisons.
• Reworks wait/terminate flow to hold process handles across waits and to validate TerminateProcess failures + confirm exit via waits.
• Expands/updates tests to cover same-name processes at other paths and executable rename scenarios.

Show a summary per file

File	Description
src/process.rs	Refactors process enumeration/matching and termination logic; adds handle ownership, cross-bitness path querying, and expanded process-behavior tests.
Cargo.toml	Updates windows-sys feature set to support ordinal string comparison used by the new matching logic.

Review details

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• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite