fix(deps): clear cargo-audit advisories via root-cause bumps

The `audit` CI job (cargo audit --deny warnings / --deny unmaintained)
denied on two advisories, both pre-existing and unrelated to the crypto
change on this branch. Resolve them at the source rather than ignoring:

- Bump indicatif 0.17 -> 0.18: 0.18 drops the `number_prefix` dependency
  entirely, clearing RUSTSEC-2025-0119 (number_prefix unmaintained). Only
  ProgressBar + ProgressStyle::default_bar() are used here, stable across
  the bump; `cargo build -p januskey` is clean on 0.18.6.
- Update anyhow 1.0.102 -> 1.0.103, the patched release for
  RUSTSEC-2026-0190 (unsound Error::downcast_mut). That API is not called
  anywhere in this codebase in any case.

number_prefix is now absent from Cargo.lock; anyhow is 1.0.103.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015qwVESTcbfanY2iJPQNoSz

Author: claude

Cargo.lock

@@ -29,7 +29,7 @@ dirs = "5"
 walkdir = "2"
 colored = "2"
 dialoguer = "0.11"
-indicatif = "0.17"
+indicatif = "0.18"
 glob = "0.3"
 whoami = "1"