feat: inspektor gadget into vhd build

[chmill-zz]

What type of PR is this?

/kind feature

What this PR does / why we need it:

this is getting inspektor gadget into agentbaker by default.

Which issue(s) this PR fixes:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version
• commits are GPG signed and Github marks them as verified

Special notes for your reviewer:

Release note:

none

[Copilot]

Pull request overview

This PR integrates Inspektor Gadget (IG) into AgentBaker's VHD build process by default. Inspektor Gadget is an eBPF-based observability tool for Kubernetes that will be pre-installed and configured on node VHDs.

Changes:

• Adds installation script (install-ig.sh) that downloads and installs IG packages for Ubuntu (via deb) and Mariner/Azure Linux (via rpm)
• Integrates IG installation into the existing VHD build pipeline via install-dependencies.sh
• Provides baseline artifacts including helper scripts for gadget import/removal and a systemd service
• Adds E2E validation and VHD content tests for IG installation
• Excludes IG installation for Flatcar, OSGuard, and Kata variants where it's not applicable

Reviewed changes

Copilot reviewed 21 out of 23 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
vhdbuilder/packer/vhd-image-builder-*.json	Adds file provisioners to copy install-ig.sh script and inspektor-gadget artifacts to all VHD build configurations
vhdbuilder/packer/install-ig.sh	New script containing all IG installation logic, including package download, installation, and configuration
vhdbuilder/packer/install-dependencies.sh	Integrates IG installation by sourcing install-ig.sh and calling installIG function
vhdbuilder/packer/test/linux-vhd-content-test.sh	Adds testInspektorGadgetAssets test to verify IG files are properly installed in VHD
parts/linux/cloud-init/artifacts/inspektor-gadget/	Baseline artifacts including import/remove gadget helper scripts, systemd service unit, and skip sentinel file
parts/common/components.json	Adds inspektor-gadget component metadata with version 0.45.0 and revision 1
schemas/components.cue	Adds optional revision field to VersionV2 schema for package versioning
e2e/validators.go	Adds ValidateInspektorGadget function to validate IG installation and functionality in E2E tests
e2e/validation.go	Integrates ValidateInspektorGadget into common Linux validation flow
vhdbuilder/packer/imagecustomizer/azlosguard/azlosguard.yml	Adds file provisioners for IG scripts needed by OSGuard builds
vhdbuilder/packer/imagecustomizer/azlosguard/scripts/azlosguard-postinstall.sh	Adds cleanup of install-ig.sh after build
.pipelines/scripts/verify_shell.sh	Excludes bash-only scripts from POSIX compliance checks
vhdbuilder/packer/test/run-pretest.sh	Removes trailing whitespace