fix(external-programs): remove cmd.exe from Windows launches

[s0up4200]

This removes the Windows cmd.exe hop from external program execution and launches configured programs directly instead. That closes the command-injection path where torrent-derived metadata could be interpreted as shell syntax.

It also updates Windows-specific tests and the external programs docs to reflect the new behavior, including the hard cut that shell wrappers must now be configured explicitly.

Summary by CodeRabbit

• New Features

  • External programs on Windows now launch directly without shell interpretation; arguments are passed literally.

• Bug Fixes

  • Improved argument handling to prevent shell metacharacter injection across platforms.

• Documentation

  • Updated guidance on external program execution with platform-specific behavior clarifications for Windows, Linux, and macOS.
  • Added recommendations for shell script handling and terminal window persistence.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: cf20646e-705e-4387-ab9b-0bc54ad83b28

📥 Commits

Reviewing files that changed from the base of the PR and between 4b05177 and 980b111.

📒 Files selected for processing (6)

• documentation/docs/features/external-programs.md
• internal/services/externalprograms/command_other.go
• internal/services/externalprograms/command_windows.go
• internal/services/externalprograms/service.go
• internal/services/externalprograms/service_test.go
• internal/services/externalprograms/service_windows_test.go

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Walkthrough

Changes transition external program execution on Windows from cmd.exe wrapper invocation to direct program launching with literal arguments. Includes documentation updates clarifying Windows-specific behavior, platform-specific command builders for Windows and non-Windows systems, unified service execution flow, and corresponding test updates.

Changes

Cohort / File(s)	Summary
Documentation documentation/docs/features/external-programs.md	Added warnings about shell script wrapping, guidance on avoiding cmd.exe wrappers, and updated cross-platform terminal emulator behavior documentation for Windows vs. Unix-like systems.
Platform-specific Command Builders internal/services/externalprograms/command_windows.go, internal/services/externalprograms/command_other.go	New files introducing buildNativeCommand with platform-specific implementations: Windows version applies SysProcAttr for process creation flags (DETACHED_PROCESS or CREATE_NEW_CONSOLE); non-Windows version uses direct CommandContext construction.
Service Execution Flow internal/services/externalprograms/service.go	Unified executeAsync path across platforms by removing separate Windows/Unix branches; replaced cmd.exe wrapping with buildNativeCommand calls for both terminal and direct execution modes; maintained post-start lifecycle and error handling.
Tests internal/services/externalprograms/service_test.go, internal/services/externalprograms/service_windows_test.go	Updated command construction assertions to expect direct program invocation with literal arguments instead of cmd.exe wrapping; added new Windows-specific test file validating SysProcAttr creation flags for terminal vs. direct modes.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• feat(automation): trigger external programs automatically via automation rules #1284: Directly modifies the same externalprograms service with related command construction and Windows SysProcAttr behavior changes.

Suggested labels

bugfix, external-programs, tests, needs-docs, area/backend

Poem

A rabbit hops free from cmd.exe's chain,
Direct paths now flourish, no wrapper refrain,
Windows and Unix, at last unified hands,
Arguments literal, as each platform demands,
Hopping with joy through these cross-platform lands! 🐰✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 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 summarizes the main change: removing cmd.exe from Windows external program launches, which is the primary objective of this PR.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/windows-external-program-launch

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