#493 Unblock auto-release on handled duplicate-import dogfood errors

Outcome

Unblocks the 2026-07-10 daily Auto Release without weakening Sentry reliability enforcement. The package import dogfood intentionally exercises merge-strategy=fail twice; its handled, pre-write duplicate refusal is now classified as expected, while an isUnhandled=true twin with identical text remains blocking.

Changes

• add a narrow handled CommandError classifier for duplicate-import refusals
• add a TDD regression proving handled and unhandled twins are partitioned correctly
• record the incident as pm-io4t with full files, test, result, live-ops, dependency, note, and learning evidence
• regenerate CHANGELOG.md with latest pm-changelog 2026.7.8

Verification

• pre-push Greptile review: confidence 5/5, no findings
• focused regression: 49/49 passing
• full repository coverage: 270 files, 5,506 tests
  • statements: 100% (34,380/34,380)
  • branches: 100% (24,588/24,588)
  • functions: 100% (6,882/6,882)
  • lines: 100% (33,039/33,039)
• typecheck and contract snapshot: pass
• ESLint, jscpd (0 clones), static quality/docstring gate, token budget: pass
• docs/skills and changelog checks: pass
• secret scan and production dependency audit: pass / no known vulnerabilities
• live Sentry gate with production token: critical=0, high=0; PM-CLI-1X expected-handled
• live telemetry gate: 0.25% finish error rate, 0 missing error-code rows
• telemetry inline flush: queue drained to zero on disk

Incident lineage

• failed scheduled run: https://github.com/unbraind/pm-cli/actions/runs/29073827938
• blocker issue: #492
• current tracker item: pm-io4t
• historical classifier precedent: pm-yohx

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Summary by cubic

Unblocks the 2026-07-10 auto-release by teaching the Sentry gate to treat the intentional, handled duplicate-import error from the package dogfood as expected. Unhandled errors with the same message remain blocking.

• Bug Fixes
  • Classify handled CommandError for duplicate-import (merge-strategy "fail": bead ...) as expected in scripts/release/sentry-telemetry-gate.mjs.
  • Add regression test that ignores the handled event while still blocking the unhandled twin.
  • Update CHANGELOG.md with pm-changelog 2026.7.8 and record incident pm-io4t.