docs(tooling): add sub-processor discriminated union to ADR-022 and traces

Amends ADR-022 §9 with the `is-sub-processor` / `processes-pii` discriminated
union spec, including the five conditional fields required when a library is a
true GDPR sub-processor. Updates the evaluate-library skill to prompt for these
fields during every trace authoring pass and adds the updated frontmatter
template. Backfills all nine existing library-decision traces with the new
fields; payload gets `processes-pii: true` (self-hosted CMS that stores user
data); all pure in-process libraries get `false / false`.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/library-decisions/_template.md

@@ -7,6 +7,14 @@ date: <YYYY-MM-DD>
 deciders: [<author>, ...]
 adr: adr-NNN | null
 lastRevalidated: null
+is-sub-processor: false
+processes-pii: false
+# include the block below only when is-sub-processor: true
+# data-sent: "<description>"
+# region: "<eu | eu-west-1 | ...>"
+# dpa-signed: false
+# sccs-required: false
+# contact: "<url or email>"
 filter-results:
   license: <SPDX id>
   types: native | "@types/<x>" | none