fix(content): purge all remaining Krenn references

Replace every occurrence of "Krenn" with "Van Maanen's Star" (or
contextual variants like VMS for locale codes, Van Maanen for proper
noun contexts). Covers CHANGELOG, briefings, workshop docs, sprint
briefings, environmental text examples, templates, ticker content,
and architecture docs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/sprints/sprint-25/copy.md

@@ -1,6 +1,6 @@
 ---
 title: "Sprint 25 — Copy Briefing"
-description: "Zone identity spec, Krenn culture profile"
+description: "Zone identity spec, Van Maanen's Star culture profile"
 type: sprint
 status: archived
 sprint: 25

docs/sprints/sprint-26/copy.md

@@ -1,6 +1,6 @@
 ---
 title: "Sprint 26 — Copy Briefing"
-description: "D-record amendments, base text elevation pass, remove handwritten Krenn content"
+description: "D-record amendments, base text elevation pass, remove handwritten Van Maanen's Star content"
 type: sprint
 status: archived
 sprint: 26