docs: add AGENTS.md and CLAUDE.md agent guide

[ykzts]

Summary

This repository had no agent guide, so conventions that are only visible in the existing code and CI configuration had to be rediscovered on every session. This PR adds an AGENTS.md describing them, following the guides in the other Publira repositories, and a CLAUDE.md that imports it with @AGENTS.md as publira/comic-viewer, publira/base-images, and publira/publira do.

Changes

• Add AGENTS.md covering the repository layout, response and documentation language, Conventional Commits with the Assisted-by trailer, pull request rules, Go API and error conventions, test placement, verification commands, and the pinning rules for CI tooling.
• Add CLAUDE.md containing @AGENTS.md.

How to Test

Documentation only; no code or build configuration is touched. The verification commands the guide documents still pass on this branch:

gofmt -l .
go vet ./...
golangci-lint run
go test ./...

Checklist

• I used a Conventional Commits style PR title.
• I tested my changes locally.
• I updated docs if needed.

Assisted-by: Claude Code:claude-opus-5

[ykzts]

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📝 Walkthrough

Walkthrough

Added AGENTS.md with repository structure, contribution, Go, testing, verification, EPUBCheck, CI, and tooling guidance. Updated CLAUDE.md to reference AGENTS.md. No exported or public entities changed.

Merge Risk: 🔵 Low · up to 05f75

The change only adds contributor documentation, but one example command can fail when copied because its image placeholder is interpreted as shell redirection. The PR is otherwise mergeable with owner follow-up to replace the placeholder with valid example paths.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the addition of AGENTS.md and CLAUDE.md agent guides.
Description check	✅ Passed	The description accurately explains the documentation-only changes and their purpose.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
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.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (2 skipped: 2 unsupported.)

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Actionable comments posted: 1

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Essentials

Run ID: 0168a0a8-963e-45da-85ec-3bc6cd4366f5

📥 Commits

Reviewing files that changed from the base of the PR and between f84ed87 and 05f75f3.

📒 Files selected for processing (2)

• AGENTS.md
• CLAUDE.md

Included review availability: 0 reviews are currently available. Your included PR review attempts over the past 7 days set your current allowance at 2 reviews per hour.

[ykzts]

@coderabbitai approve

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✅ Action performed

Comments resolved and changes approved.