When a slice plan (S03-PLAN.md) was pre-created during roadmapping
but plan-slice never ran to generate per-task files (tasks/T01-PLAN.md),
deriveState returned 'executing' phase. execute-task then failed because
the task plan didn't exist, creating an infinite restart loop.
Fix: In deriveState, when the tasks directory exists but has zero .md
files and the slice plan references tasks, return 'planning' phase
instead of 'executing'. This causes plan-slice to dispatch and generate
the missing task plans.
Tests updated: 6 test files that create synthetic state fixtures now
include a stub task plan file so their 'executing' phase assertions
remain valid.
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