Windows context menu, JustPaste, video resolutions, managed downloads (2.6.0)

[JustSuperHuman]

Summary

• File Explorer context menu (Windows): just context install adds a single-level JustTools flyout with entries per file type. It is served by the new justtools_shell.dll and registered per user, as a Windows 11 package (signed package or Developer Mode) or as classic verbs. Each entry runs an ordinary headless command in a console window that closes by itself.
• JustPaste: justpaste <url> / --clipboard saves whatever a link points at — files as-is, pages through yt-dlp, then the media a page declares. Never overwrites.
• JustVideo resolutions: --resolution 480p|720p|1080p|1440p|4k|source, plus the launcher row.
• Managed downloads: a missing yt-dlp or FFmpeg is downloaded automatically on every platform into a per-user folder and verified against the vendor's SHA-256; yt-dlp --update runs whenever twelve hours have passed.
• Also lands justip and URL inputs for the media tools, and bumps to 2.6.0.

Cross-platform

The extension crate is empty off Windows and the menu model is plain Rust tested everywhere. Windows archives gain justtools_shell.dll; other archives are unchanged. A new non-blocking CI step downloads and runs the managed yt-dlp and FFmpeg on all six targets.

Test plan

• fmt, clippy -D warnings, full tests, Rust 1.90 check, release build (Windows x64, local)
• Context menu registered and exercised through Explorer's COM activation
• Real yt-dlp and FFmpeg downloads verified and run (Windows x64, local)
• Six-platform matrix green

🤖 Generated with Claude Code

[sentry]

Bug: Providing duplicate URLs as command-line arguments causes a misleading error because the input count is checked after deduplication.
_{Severity: MEDIUM}

Suggested Fix

The validation logic should be adjusted. Instead of comparing the count of deduplicated URLs to the original input count, the check should happen before deduplication, or the check should be removed in favor of simply using the deduplicated list of URLs. The current clipboard handling logic already correctly deduplicates URLs without this faulty check and could serve as a model.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: src/commands/paste.rs#L638-L642

Potential issue: When multiple identical URLs are provided as command-line arguments,
the `links()` function deduplicates them. Subsequently, a check at
`src/commands/paste.rs:638` compares the deduplicated URL count with the original input
count. This discrepancy (`urls.len() < options.inputs.len()`) incorrectly triggers an
error stating 'every input must be an http(s) link', even though all inputs are valid
URLs. This can happen if a user accidentally provides the same URL twice or if a script
does so.

_{Did we get this right? 👍 / 👎 to inform future reviews.}