Look at BufMut usage

[ties]

I looked at the usage of BytesMut and realised that one case could be a bit cleaner:

-    let mut buffer = BytesMut::with_capacity(common_header.length as usize);
-    buffer.resize(common_header.length as usize, 0);
+    let mut buffer = BytesMut::zeroed(common_header.length as usize);

I ended up bikeshedding some more cases. I think that in general most usage of Bytes can be replaced by Buf which would allow a reference to a u8 slice to be passed in.

[Copilot]

Pull Request Overview

This PR optimizes BufMut usage throughout the codebase by replacing inefficient buffer allocation patterns with more direct alternatives and improving capacity management.

• Replaces BytesMut::with_capacity() + resize() with BytesMut::zeroed() for cleaner initialization
• Substitutes BytesMut with direct slice references where appropriate to avoid unnecessary allocations
• Adds proper capacity allocation for buffer operations to improve performance

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/parser/mrt/mrt_record.rs	Optimizes buffer initialization and adds capacity pre-allocation
src/parser/mrt/mrt_header.rs	Replaces BytesMut with direct slice references for parsing
src/models/network/asn.rs	Improves PartialOrd implementation and adds capacity pre-allocation
.claude/settings.local.json	Adds Claude configuration file for development permissions

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