Fix Fedora manual-install CI failures by removing rev dependency from installer fallback

[Copilot]

The Fedora manual install job started failing across branches because INSTALL.sh fallback logic depended on rev, which is not guaranteed on minimal Fedora images. This caused release version parsing to fail and package download fallback to abort.

• Installer fallback parsing (cross-distro hardening)

  • Replaced rev | cut | rev parsing in INSTALL.sh fallback paths with a POSIX shell while read parser using parameter expansion.
  • Added a dedicated extract_release_version helper to parse redirect location lines.
  • Added validation to ignore malformed extracted values (empty or containing /) so fallback behavior remains safe and predictable.

• Targeted regression coverage

  • Added a focused unit test for fallback release-version extraction:
    • tests/unit/test_unit_install_extract_release_version.sh
  • Covers both a valid redirect line and an invalid path-like redirect value.

# before
... | grep location | tr -d '\r' | rev | cut -d / -f 1 | rev | cut -d v -f 2

# after
... | grep location | tr -d '\r' | extract_release_version

> [!WARNING]
>
>

[plengauer]

Hello, thanks for contributing for the first time!

[plengauer]

@copilot see my comment

[Copilot]

Pull request overview

This PR hardens the manual installer fallback path by removing the rev dependency from release-version extraction and adds focused regression coverage for the parsing behavior.

Changes:

• Adds extract_release_version in INSTALL.sh using POSIX shell parsing.
• Replaces all fallback rev | cut | rev pipelines with the new helper.
• Adds a unit test covering valid and invalid redirect header parsing.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
INSTALL.sh	Adds and uses a POSIX release-version extraction helper in package download fallbacks.
tests/unit/test_unit_install_extract_release_version.sh	Adds regression assertions for release redirect parsing behavior.