release: bump version to v0.3.0

[ArangoGutierrez]

Summary

• Bump version string from 0.2.18 to 0.3.0 in cmd/cli/main.go
• Set CHANGELOG date from Unreleased to 2026-03-30

What's in v0.3.0

This is a major release covering all work since v0.2.18 (2025-12-13):

• Production-Grade Cluster Networking — private subnets, SSM transport, separate security groups, NLB for HA (feat: add cluster networking cache constants and struct fields #720-728)
• Custom Templates — user-provided scripts at provisioning phases (feat(api): add CustomTemplate type and TemplatePhase enum (#565) #701-706)
• RPM Distribution Support — Rocky Linux, Amazon Linux 2023, Fedora 42 (feat(templates): add RPM support to NVIDIA driver #676-681)
• E2E Test Tiering — smoke (pre-merge) and full (post-merge) tiers (ci: split E2E tests into smoke (pre-merge) and full (post-merge) tiers #740)
• ARM64 Support — architecture inference from instance type (fix(aws): infer AMI architecture from instance type for arm64 support #669)
• Comprehensive Documentation — guides for custom templates, GitHub Action, multinode clusters, E2E testing
• Test Infrastructure — expanded coverage scope, 40% threshold gate, custom templates E2E
• Dependency Updates — AWS SDK v2 bumps (chore(deps): Bump github.com/aws/aws-sdk-go-v2 from 1.41.4 to 1.41.5 #741-745)

Test plan

• Verify holodeck --version shows 0.3.0
• CI passes (unit tests, lint, build)

[coveralls]

Pull Request Test Coverage Report for Build 23747792661

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 45.802%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/cli/main.go	0	1	0.0%

Totals
Change from base Build 23747562636:	0.0%
Covered Lines:	4975
Relevant Lines:	10862

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💛 - Coveralls