Add plugin-shared/ as the canonical source of truth for cross-skill
references and templates. Holds full versions of methodik, artefakt-
pipeline, kommunikationsregeln, recherche-regeln, export-formate,
and the two templates.
Per workflow-skill design rules (no reference chains, no hardcoded
cross-skill paths), Skills do NOT reference plugin-shared/ at
runtime. Each Skill carries curated extracts in its own references/.
drift-check.sh (added in step 11) will compare those extracts against
the master here.
Step 1 of i2s-skill-split refactor.
Philipp Sieder
7cf1c7c61e