Add --arch flag to build and publish commands for single-arch builds

[hcastc00]

Summary

• Add --arch flag to build and publish commands to allow building for a single architecture instead of all architectures defined in the manifest
• Accepts both full names (linux/arm64, linux/amd64) and shorthands (arm, arm64, amd64, x64, etc.)
• Validates that the requested architecture is supported by the package manifest before building

Usage

# Build only for arm64
dappnodesdk build --arch arm64

# Build only for amd64
dappnodesdk build --arch amd64

# Full architecture names also work
dappnodesdk build --arch linux/arm64

# Works with publish too
dappnodesdk publish patch --arch arm64

Changed files

• src/commands/build/index.ts - Register --arch CLI option
• src/commands/build/types.ts - Add arch to BuildCommandOptions
• src/commands/build/handler.ts - Filter architectures + normalizeArchitecture helper
• src/commands/publish/index.ts - Register --arch CLI option
• src/commands/publish/types.ts - Add arch to PublishCommandOptions
• src/commands/publish/handler.ts - Filter architectures using shared helper

Test plan

• Build a multi-arch package with --arch arm64 and verify only arm64 image is built
• Build with --arch amd64 and verify only amd64 image is built
• Verify shorthands (arm, arm64, amd64, x64) resolve correctly
• Verify error when using --arch with an unsupported architecture for the package
• Verify builds without --arch still build all architectures as before

[github-actions]

Dappnode bot has built and pinned the built packages to an IPFS node, for commit: 34828b3

This is a development version and should only be installed for testing purposes.

1. Package dappnodesdk.public.dappnode.eth

Install link

Hash: /ipfs/QmPJW3pa45L4ryC1dnyztYkJPGgQVB6VDgB5nUvsqVyBkg

(by dappnodebot/build-action)

[Marketen]

I wouldnt let the sdk publish something with only 1 arch if 2 are present in the manifest. This may provoke that we stop supporting an arch unintentionally in the future