Change molecule step completion instructions to use `gt mol step done`
instead of `bd close`. This ensures polecats get fresh context between
each step, which is critical for multi-step review workflows like
shiny-enterprise where each refinement pass should have unbiased attention.
The `gt mol step done` command already:
1. Closes the step
2. Finds the next ready step
3. Respawns the pane for fresh context
But polecats were being instructed to use `bd close` directly, which
skipped the respawn and let them run through entire workflows in a
single session with accumulated context.
Updated:
- prime_molecule.go: step completion instructions
- mol-polecat-work.formula.toml
- mol-polecat-code-review.formula.toml
- mol-polecat-review-pr.formula.toml
Fixes: hq-0kx7ra