fix: remove leading zeros from ADR titles and add linter

[maruiz93]

Summary

• Updates the writing-adrs skill to document that ADR title numbers must not have leading zeros (zero-padded format is only for filenames)
• Fixes 4 existing ADRs (17, 19, 25, 27) that had zero-padded numbers in their title: frontmatter and # heading
• Extends hack/lint-adr-numbers to catch leading zeros in titles and headings going forward

Test plan

• make lint passes
• Linter correctly catches leading zeros (verified by temporarily reverting ADR 17)
• Linter passes on all fixed ADR files

🤖 Generated with Claude Code

[github-actions]

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Commit: cd6182c87fd98310eeaaa2f8c40cd0a5b8610cc3

[fullsend-ai-review]

Review: #719

Head SHA: cd6182c
Timestamp: 2026-05-07T00:00:00Z
Outcome: approve

Summary

Clean, well-scoped fix. The PR removes leading zeros from the title: frontmatter and # heading in four ADRs (17, 19, 25, 27) and extends the existing hack/lint-adr-numbers script to catch this pattern going forward. The SKILL.md is updated to document the convention. All changes verified against the full set of ADR files — the four fixed files are the only ones that had the issue, and no ADRs were missed. The linter refactoring from early-exit to a has_errors flag is correct and allows both the duplicate-number and leading-zeros checks to run before reporting.

Findings

Info

• [Style/conventions] hack/lint-adr-numbers:3 — The file header comment still reads "Check for duplicate ADR numeric identifiers" but the script now also checks for leading zeros in titles. Consider updating to reflect the expanded scope (e.g., "Check ADR numeric identifiers for duplicates and formatting").

Footer

Outcome: approve
This review applies to SHA cd6182c87fd98310eeaaa2f8c40cd0a5b8610cc3. Any push to the PR head clears this review and requires a new evaluation.