[Vela OTA] Sub-Issue 11: Delta update engine — binary diff/patch

[JusterZhu]

Sub-Issue 11: Delta Update Engine

Implement a binary delta engine that enables efficient incremental updates
by transmitting only the changed bytes between versions.

Design

Vela Delta is a standalone crate (vela-delta) in the vela-core workspace:

vela-delta/
├── src/
│   ├── lib.rs
│   ├── diff.rs
│   ├── patch.rs
│   └── manifest.rs
└── Cargo.toml

API

• generate_delta(old: &[u8], new: &[u8]) -> DeltaResult<Vec<u8>>
• apply_patch(base: &[u8], patch: &[u8]) -> DeltaResult<Vec<u8>>
• DeltaManifest — metadata for delta bundles

Integration with FlashPack

• Uses PayloadType::Delta when building delta FlashPacks
• Includes delta.manifest in the .fpk tar archive
• Version baseline validation via requires_version in FpkHeader