Add shared Renovate config presets

[toshi0806]

Summary

Introduce org-wide Renovate presets so each repository can extend a single shared config instead of duplicating its full configuration. Currently the same Renovate config is copy-pasted across multiple repos (latex-environment / latex-release-action / thesis-management-tools share an identical file; tdig / tenbin_* / elixir_dnstap share another).

Presets

• default.json — common base: Asia/Tokyo, dependency dashboard, semantic commits, and auto-merge limited to patch / digest updates only.
• latex.json — extends default + workarounds:all; rules for github-actions / dockerfile (pinDigests) and npm (rangeStrategy: bump). Weekly schedule (Sun 21:00).
• elixir.json — extends default; mix manager only, lockFileMaintenance, grouped minor/patch/digest auto-merge. Weekly schedule (Mon before 6am).

Usage (follow-up PRs)

Each repository's renovate.json collapses to a single line:

// LaTeX ecosystem repos
{ "extends": ["github>smkwlab/.github:latex"] }

// Elixir repos
{ "extends": ["github>smkwlab/.github:elixir"] }

Rollout plan

1. This PR — add the presets (must merge first; extends cannot resolve until they exist on the default branch).
2. Migrate existing configs (latex-environment / latex-release-action / thesis-management-tools, and the Elixir repos) to extends.
3. New Phase 1 adoption: texlive-ja-textlint / ai-academic-paper-reviewer / ai-reviewer.

Notes

• Auto-merge scope is intentionally narrow (patch/digest) per agreed policy; minor/major remain manual review.
• Renovate App stays on Selected repositories to avoid touching student repositories under the org.

[Copilot]

Pull request overview

This PR adds shared Renovate preset configurations to centralize dependency update policy across repositories in the smkwlab org, allowing individual repos to extends a single canonical config instead of duplicating full Renovate settings.

Changes:

• Added a default.json preset providing a shared base (timezone, dependency dashboard, semantic commits, patch/digest-only auto-merge).
• Added a latex.json preset for LaTeX ecosystem repositories (workarounds + manager-specific rules and weekly schedule).
• Added an elixir.json preset for Elixir repositories (mix-only, lock file maintenance, grouping and scheduling).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
default.json	Introduces the shared Renovate baseline preset (timezone/dashboard/semantic commits + limited auto-merge rules).
latex.json	Adds a LaTeX-oriented preset extending the shared base with manager-specific rules and a weekly schedule.
elixir.json	Adds an Elixir-oriented preset extending the shared base with mix-only configuration, grouping, and scheduling.

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[toshi0806]

ご指摘ありがとうございます。これは意図的な例外です。

org全体の auto-merge ポリシーは patch/digest 限定（default.json）ですが、Elixir リポジトリ群は既存運用で minor / lockFileMaintenance も自動マージしており、hex パッケージが概ね semver 準拠で安定しているため、その挙動を維持する設計としています。

意図が伝わるよう、elixir.json のルール description に「org方針への意図的な例外であり、既存Elixir repoの挙動を維持する」旨を明記しました（commit b892108）。挙動自体は変更していません。

[toshi0806]

レビュー対応 (Copilot指摘)

elixir.json の auto-merge が patch/digest だけでなく minor / lockFileMaintenance も含む、というご指摘について：

結論: 意図的な例外として現状維持します。

• org全体の auto-merge ポリシーは patch/digest 限定（default.json で定義）
• Elixir 系リポジトリ（tdig / tenbin_* / elixir_dnstap）は既存運用で minor も自動マージしており、hex パッケージが概ね semver 準拠で安定しているため、この挙動を維持
• 意図を明確化するため elixir.json のルール description に例外である旨を明記（commit b892108）。挙動の変更はありません

PR説明の「auto-merge limited to patch/digest」は default.json の方針を指すもので、elixir.json はその意図的な例外、という位置づけです。

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.