[Clamd] Update to 1.4.6

[FreddleSpl0it]

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• I've read the contribution guidelines and wholeheartedly agree them

What does this PR include?

Short Description

Bump ClamAV from 1.4.2 to 1.4.6 to patch 8 CVEs disclosed in the 1.4.6/1.5.4 release, most notably CVE-2026-20337 and CVE-2026-20338 (high-severity DoS via crafted ZIP/PDF files, PoC public).

The 1.4.6 source vendors a Rust dep that requires edition2024 (Cargo ≥ 1.85), which Alpine 3.21 does not ship. The clamd build image is therefore bumped from Alpine 3.21 to Alpine 3.24.

Affected Containers

• clamd-mailcow

Did you run tests?

What did you tested?

• Image rebuild on Alpine 3.24
• Container startup and healthcheck
• clamd --version / freshclam --version inside the container
• freshclam signature update
• Direct EICAR scan via clamdscan (unix socket) and clean-file scan
• clamd TCP:3310 reachability from rspamd
• End-to-end: EICAR mail piped through rspamc symbols (rspamd → clamd)

What were the final results? (Awaited, got)

• Awaited: ClamAV 1.4.6 running, signatures loaded, EICAR flagged, mail path rejects virus. Got: exactly that.
• Container healthy, ClamAV 1.4.6 on Alpine 3.24.1, signatures up-to-date.
• Direct EICAR scan → Eicar-Test-Signature FOUND; clean file → OK.
• End-to-end EICAR via rspamc → Symbol: VIRUS_FOUND (2000.00), Action: reject.