Release Gloss 1.0.5 with legacy extension migration

[SunChJ]

Summary

• migrate recognizable legacy browser extension directories that predate the .gloss-managed marker
• keep overwrite protection for directories with a different manifest or file layout
• bump Gloss to 1.0.5 (build 18) and add release notes

Root cause

Older unpacked extension directories could exist at Gloss's managed Application Support path without the management marker. When bundled extension contents changed, Gloss rejected that directory as unmanaged before it could refresh the copy, so Show Extension displayed an error.

User impact

Existing installations can open and refresh a verified legacy extension directory without deleting or reinstalling it manually. Unrelated or modified directories remain protected from overwrite.

Validation

• swift test — 226 XCTest tests and 70 Swift Testing tests passed; expected live smoke tests skipped
• swift format lint --strict Sources/Gloss/BrowserExtensionFiles.swift Tests/GlossAppTests/BrowserExtensionFilesTests.swift
• plutil -lint Resources/Info.plist
• git diff --check