Go port - phase 1 - base framework

[offbyone]

Begin porting this CLI to go

• Justfile targets: just go-build, go-test, etc... just ci-all to run CI for both.
• Conventional pkg/ and cmd/ layout
• depends on the cobra CLI interface
• linter rules
• integrated go CI

The eventual result will be a -beta CLI version in parallel with the C# CLI

• Did you write/update appropriate tests
• Release notes updated (if appropriate) — not user-facing yet (parallel Go port)
• Appropriate logging output
• Issue linked — tracking via PR stack
• Docs updated (or issue created)
• New package licenses are added to ThirdPartyNotices.txt (if applicable)

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PR Stack (Go port)

• 👉 Go port - phase 1 - base framework #1500 — Phase 1: Base framework (this PR)
• Phase 2 of the go port - generate-script #1501 — Phase 2: generate-script
• Phase 3: GitHub API client + all shared commands (Go port) #1533 — Phase 3: GitHub API client + shared commands
• Phase 4: Cloud storage clients + archive orchestration + GHES version checker (Go port) #1535 — Phase 4: Cloud storage + archive orchestration + GHES version checker
• Phase 5: gei migrate-repo, migrate-org, alert migration commands (Go port) #1536 — Phase 5: gei migrate-repo, migrate-org, alert migration commands
• Phase 6: ADO API client + all ado2gh commands (Go port) #1537 — Phase 6: ADO API client + all ado2gh commands
• Phase 7: BBS API client + all bbs2gh commands (Go port) #1538 — Phase 7: BBS API client + all bbs2gh commands

[github-actions]

Unit Test Results

    1 files      1 suites   10m 24s ⏱️
1 030 tests 1 030 ✅ 0 💤 0 ❌
1 031 runs  1 031 ✅ 0 💤 0 ❌

Results for commit b7a33e4.

♻️ This comment has been updated with latest results.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
ado2gh	71%	69%	741	➖
gei	81%	73%	608	✔
bbs2gh	83%	78%	667	✔
Octoshift	84%	74%	1819	✔
Summary	81% (7953 / 9843)	74% (1959 / 2665)	3835	✔