chore: standardize license header tooling

[rice-riley]

Description

Standardizes Apache-2.0 source-header formatting and validation with google/addlicense while preserving component ownership.

• Pins addlicense v1.2.0 for the Go agent tooling.
• Keeps the operator format/check targets scoped to tracked operator sources.
• Makes the agent format/check targets cover tracked agent sources, including the Go rewrite, while excluding vendored dependencies.
• Makes the root format/check targets own root-level sources and delegate to both component targets.
• Runs the repo-wide header check from the unfiltered Lint CI workflow and keeps the focused Agent Go CI check.
• Removes the remaining Makefile references to the deleted format_license.py implementation.

Third-party dependency license allowlisting is intentionally out of scope and will be handled in a separate PR.

Part of #219

Validation

• make license-fmt
• make license-header-check
• make unit-tests (agent/go)
• make vet (agent/go)
• make lint (agent/go)
• make build (agent/go)
• yamllint -c ci/yamllint.yaml .github/workflows/lint-ci.yaml .github/workflows/agent-go-ci.yaml
• Verified wrong headers fail only their owning component check and the aggregate root check.

Checklist

• I am familiar with the Contributing Guidelines.
• My commits are signed off (git commit -s) per the DCO.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Configuration used: Path: .coderabbit.yaml

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📥 Commits

Reviewing files that changed from the base of the PR and between a437d9b and 7255625.

📒 Files selected for processing (7)

• .github/workflows/agent-go-ci.yaml
• .github/workflows/lint-ci.yaml
• Makefile
• agent/Makefile
• agent/go/Makefile
• agent/go/deps.mk
• operator/Makefile

---

📝 Walkthrough

Walkthrough

The build configuration installs the configured addlicense version. Make targets use addlicense to format tracked source files and validate Apache-2.0 SPDX headers while excluding generated files. Lint targets and CI jobs run the license-header validation.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers: ayuskauskas, lockwobr

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the standardization of license header tooling described by the changeset.
Description check	✅ Passed	The description directly explains the license tooling changes, scope, CI updates, validation, and out-of-scope work.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch agent-license-219

---

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@agent/go/deps.mk`:
- Around line 50-52: Update the addlicense target to validate the existing
$(ADDLICENSE) against ADDLICENSE_VERSION before reuse, rather than only checking
that it is non-empty. Require an executable file and add a version stamp or
supported-version check tied to ADDLICENSE_VERSION; reinstall when validation
fails.

In `@agent/go/Makefile`:
- Around line 54-56: Update the license validation pipeline in the wrong-file
check to match SPDX-License-Identifier: Apache-2.0 only within the leading
header comment block, rather than anywhere in the first 20 lines. Preserve the
generated-file exemption and report files whose header lacks the exact Apache
identifier.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

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Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Enterprise

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📥 Commits

Reviewing files that changed from the base of the PR and between e5a3ab6 and 3e8998b.

📒 Files selected for processing (2)

• agent/go/Makefile
• agent/go/deps.mk

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.github/workflows/lint-ci.yaml:
- Line 54: Update the actions/setup-go step to reference the reviewed commit SHA
instead of the mutable v7 tag, while retaining the existing version comment.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Enterprise

Run ID: 0fd27ae0-3f4b-486c-a7ba-3d66148e0473

📥 Commits

Reviewing files that changed from the base of the PR and between a437d9b and 804039e.

📒 Files selected for processing (7)

• .github/workflows/agent-go-ci.yaml
• .github/workflows/lint-ci.yaml
• Makefile
• agent/Makefile
• agent/go/Makefile
• agent/go/deps.mk
• operator/Makefile

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.