Fix Instagram media extraction and Safari bookmarklet support

[pzzzy]

What changed

• Restores source-media selection for current Instagram posts, carousels, reels, and stories.
• Recovers blob-backed reel video from loaded Instagram MP4 resources, excludes audio-only DASH tracks, and removes byte-range parameters before opening the source.
• Prefers the centered visible media and the largest image srcset candidate while filtering profile images.
• Adds a compact Safari bookmarklet distribution and synchronizes version 5.2.8 across every published language page.
• Adds deterministic tests, reproducible build tooling, contributor instructions, and a minimal read-only CI workflow.

Why

Instagram now commonly exposes reels as blob: URLs backed by separate DASH resources, while permalink metadata may contain only a cover image. The previous fallback could therefore open an audio track, profile image, adjacent feed media, or no usable source.

Safari also failed to run the fully percent-encoded async payload reliably. The generated Safari form now evaluates without returning the async Promise and encodes only URL-breaking characters, reducing the bookmark address from 6,443 to 4,289 characters.

Impact

Users can open the currently visible source image or video again on modern Instagram, including from macOS Safari, without an extension or external service.

Validation

• npm run build
• npm test — 9 tests passing
• git diff --check
• Workflow YAML parse validation
• Live public Instagram reel DOM/resource inspection
• Successful manual test of the compact bookmarklet in macOS Safari