feat: support custom VM IDs in create-l1 and Ansible

[owenwahlgren]

Summary

• Add --vm-id flag to tools/create-l1 so it can deploy chains with any AvalancheGo VM plugin, not just SubnetEVM
• Add Ansible support for installing custom VM plugin binaries on validator nodes

Motivation

The create-l1 tool currently hardcodes constants.SubnetEVMID. This makes it impossible to deploy custom VMs (DAML VM, MoveVM, etc.) without forking the tool. This PR makes the VM ID configurable while keeping SubnetEVM as the default.

Changes

• tools/create-l1/main.go: Add --vm-id flag, parse with ids.FromString(), pass to IssueCreateChainTx
• ansible/roles/avalanchego/defaults/main.yml: Add custom_vm_id and custom_vm_binary_path variables
• ansible/roles/avalanchego/tasks/main.yml: Add task to copy custom VM binary to plugins directory

Usage

# Default (SubnetEVM, unchanged behavior):
./create-l1 --network=fuji --validators=1.2.3.4

# Custom VM:
./create-l1 --network=fuji --vm-id=nNQ83pDiUEV1sobcMFWiJK1QZD38Rm56TC5SU2eKMqmnYZsdF --genesis=daml-genesis.json --validators=1.2.3.4

Test plan

• go build compiles with no errors
• Default behavior unchanged (SubnetEVM when --vm-id omitted)
• Custom VM ID accepted and passed to IssueCreateChainTx
• Ansible custom VM installation tested with DAML VM deployment to Fuji

Closes #7