[Bug]: /speckit-converge is not idempotent — re-runs append duplicate remediation tasks

[jabelk]

Version

spec-kit v1.0.1 (.claude/skills/speckit-converge/SKILL.md)

Description

/speckit-converge only checks that tasks.md exists before assessing the codebase and appending remediation tasks. It keeps no persisted evidence that /speckit-implement actually ran against the current task list, and it does not map its findings onto existing unchecked tasks before appending.

Two consequences:

1. Invoked early (before implement has run, or after a partial implementation), it appends remediation tasks for work that is already represented by existing unchecked tasks — now under new IDs, splitting traceability for the same work across two task entries.
2. Invoked twice (e.g. converge → partial fix → converge again), gaps found both times are appended both times.

Expected behavior

• Converge verifies prerequisite state (an implementation checkpoint, or at minimum warns loudly when tasks.md contains unchecked tasks that overlap its findings).
• Before appending, each finding is compared against existing unchecked tasks; covered work is reused/updated rather than duplicated, and only genuinely new gaps get new IDs.

Context

Found while upgrading a template fleet from 0.5.0 to v1.0.1 and reviewing the newly vendored command. Related in spirit to the duplicate-detection work in #2968, but on the tasks.md side rather than GitHub issues.