v1.9.0

What's Changed

• chore: bump version to 1.9.0 (9ecb93f)
• chore: bump version to 1.9.0 (1cf552a)
• docs: document doctor command in root and package guides (48fd1e9)
• feat: add doctor command for project health diagnostics (775d428)
• test: add canonical package smoke tests (246ec6d)
• docs: add post-release checklist, release snapshot, and v1.9.0 roadmap (a19aaae)
• fix: --base-dir writes AGENTS.md under baseDir and adds --skip-existing flag (29f842f)
• fix: respect --base-dir for AGENTS.md in retrofit command (d5c33cd)
• Initial plan (c59f4fb)
• Initial plan (7457421)

Full Changelog: v1.8.1...v1.9.0