fix: prevent integer overflow in DiskHealthReport and document pinned Ookla CLI version

[laurentiu021]

Summary

Fix two remaining bugs from the full code review (BUG-008, BUG-009).

Changes

DiskHealthReport.cs (BUG-009)

• Fixed potential integer overflow in HealthPercent when ReadErrors or WriteErrors
  exceed int.MaxValue. The cast (int)ReadErrors.Value * 5 could wrap to a negative
  number, causing the score to increase instead of decrease.
• Fix: use long arithmetic (ReadErrors.Value * 5L) before clamping with Math.Min(..., 20L).

SpeedTestService.cs (BUG-008)

• Added maintenance comment documenting the pinned Ookla CLI version (1.2.0) and
  explaining the update procedure. Authenticode signature verification ensures binary
  integrity regardless of version.

Previously fixed (verified, no action needed)

• BUG-001 (WindowsFeaturesVM CanExecute) — already calls NotifyCanExecuteChanged
• BUG-002 (DuplicateFileGroup WastedBytes) — already has [NotifyPropertyChangedFor]
• BUG-003 (TuneUpService HRESULT) — already checks return value
• BUG-004 (UpdateService pre-release) — already filters in Map()
• BUG-005 (ServiceManagerService StartPending) — already checks status
• BUG-006 (DiskAnalyzerService empty dirs) — correctly tracks exceptions
• BUG-007 (WindowsUpdateVM Shutdown) — already uses ?.Shutdown()
• SEC-001 (SpeedTestService fake hashes) — no fake hashes exist; uses Authenticode

Testing

• Build: 0 errors
• No behavior change for normal values (deduction capped at 20 regardless)

Summary by CodeRabbit

• Bug Fixes

  • Fixed an integer overflow issue in disk health percentage calculations.

• Documentation

  • Updated changelog with maintenance notes and fix documentation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 9c44e241-7d70-4a96-b6b3-2a06d8f33d26

📥 Commits

Reviewing files that changed from the base of the PR and between 98952ae and 3275976.

📒 Files selected for processing (3)

• CHANGELOG.md
• SysManager/SysManager/Models/DiskHealthReport.cs
• SysManager/SysManager/Services/SpeedTestService.cs

📜 Recent review details

🔇 Additional comments (3)

SysManager/SysManager/Services/SpeedTestService.cs (1)

313-316: LGTM!

SysManager/SysManager/Models/DiskHealthReport.cs (1)

77-78: LGTM!

CHANGELOG.md (1)

17-21: LGTM!

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📝 Walkthrough

Walkthrough

This PR applies a targeted integer overflow prevention fix to DiskHealthReport.HealthPercent calculations and adds maintenance documentation to SpeedTestService regarding Ookla CLI versioning. The changelog documents both updates.

Changes

Bug Fix and Maintenance Updates

Layer / File(s)	Summary
DiskHealthReport integer overflow prevention SysManager/SysManager/Models/DiskHealthReport.cs, CHANGELOG.md	HealthPercent now computes error-count penalties using long arithmetic (* 5L, Math.Min(..., 20L)) before casting to int, eliminating overflow risk during multiplication and clamping. Changelog entry documents the fix.
SpeedTestService Ookla CLI documentation SysManager/SysManager/Services/SpeedTestService.cs	EnsureOoklaAsync gains maintenance comments clarifying that the Ookla CLI version (1.2.0) is pinned and that Authenticode signature verification ensures binary integrity independent of the pinned version.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related PRs

• laurentiu021/SystemManager#294: Overlaps with SpeedTestService.EnsureOoklaAsync documentation about pinned Ookla CLI version and security hardening for downloads.
• laurentiu021/SystemManager#266: DiskHealthReport.HealthPercent change impacts the disk-health input used by HealthScoreService to compute overall dashboard health scores.
• laurentiu021/SystemManager#403: Changes to SpeedTestService.EnsureOoklaAsync are in the same method that the referenced PR hardens for Ookla execution and download safety.

Poem

🐰 A rabbit hops through overflow's snare,
with long arithmetic cast with care,
while Ookla's CLI stays pinned so tight,
and Authenticode keeps downloads right!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main changes: fixing integer overflow in DiskHealthReport and documenting the pinned Ookla CLI version, which directly aligns with the changeset.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/disk-health-overflow-and-ookla-version

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