fix: use basic parsing for Windows installer downloads

[ceodaradigu]

Fixes #195.

What changed

• pass -UseBasicParsing to both Invoke-WebRequest calls in the Windows bootstrap script
• keep all three shipped copies of the script in sync
• add a deterministic PowerShell 5.1 regression test using local ZIP and checksum fixtures
• run the regression in the Windows Install E2E GitHub Actions job

Why

Windows PowerShell 5.1 can attempt to use the legacy Internet Explorer parser when Invoke-WebRequest is called without -UseBasicParsing. On systems where IE is unavailable or its first-launch configuration is incomplete, bootstrap fails before the agent can be installed.

Verification

• PowerShell parser check passes for all modified scripts and the new test
• powershell.exe -NoProfile -ExecutionPolicy Bypass -File tests/ensure-monk-agent-basic-parsing.ps1
• result: ensure_basic_parsing_status=pass downloads=2
• regression is wired into .github/workflows/install-e2e.yml
• git diff --check passes

[ceodaradigu]

Revalidated this patch against the current main release v0.1.54 (2a4f9cf) on Windows PowerShell 5.1. Results: ensure_basic_parsing_status=pass downloads=2; PowerShell parser validation passed for 4/4 files; git diff --check upstream/main...HEAD passed. The branch is already based on v0.1.54, so no rebase or code changes are required.

[ceodaradigu]

The Install E2E workflow for the latest commit is currently awaiting approval before any jobs can start (fork contribution). Could a maintainer approve the workflow run when convenient? The Windows PowerShell 5.1 regression passes locally with ensure_basic_parsing_status=pass downloads=2, and it is now wired into that workflow.

[ceodaradigu]

Updated this branch onto the current v0.1.55 main release (dbb6ce4) and preserved the Windows Install E2E regression step. Fresh validation on the rebased head (789e809): ensure_basic_parsing_status=pass downloads=2; all three shipped installer copies remain byte-identical; and git diff --check upstream/main...HEAD passes. The PR is now current and mergeable against v0.1.55.

[nooga]

Closing as already fixed — -UseBasicParsing was added to both Invoke-WebRequest calls in commit ac9fe06 (2026-08-07), which landed independently a couple of days after you opened this.

Your diagnosis and your patch were both correct at the time of filing; that's recorded in triage. Nothing further needed here — thanks.