Trim the skill and add Paratext anticipation guidance

Halves the skill to its decision rules: drops the wrong-tool section and
compresses the investigation narratives into the rules they produced.
Adds an anticipate-only Paratext section: a watchlist of packages whose
bumps can affect the merged lexicon plugin that Paratext loads into its
own process, an AssemblyRef diff of the merged plugin between base and
branch builds, and instructions to hand any contract change to the user
as deliberate follow-up work rather than fixing it mid-run.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: jasonleenaylor