feat(voyage)!: marketplace handoff — rename plugins/ultraplan-local to plugins/voyage [skip-docs]

Session 5 of voyage-rebrand (V6). Operator-authorized cross-plugin scope.

- git mv plugins/ultraplan-local plugins/voyage (rename detected, history preserved)
- .claude-plugin/marketplace.json: voyage entry replaces ultraplan-local
- CLAUDE.md: voyage row in plugin list, voyage in design-system consumer list
- README.md: bulk rename ultra*-local commands -> trek* commands; ultraplan-local refs -> voyage; type discriminators (type: trekbrief/trekreview); session-title pattern (voyage:<command>:<slug>); v4.0.0 release-note paragraph
- plugins/voyage/.claude-plugin/plugin.json: homepage/repository URLs point to monorepo voyage path
- plugins/voyage/verify.sh: drop URL whitelist exception (no longer needed)

Closes voyage-rebrand. bash plugins/voyage/verify.sh PASS 7/7. npm test 361/361.

.claude-plugin/marketplace.json

@@ -21,9 +21,9 @@
       "description": "Multi-agent workflow for analyzing, reporting, and optimizing Claude Code configuration across your entire machine"
     },
     {
-      "name": "ultraplan-local",
-      "source": "./plugins/ultraplan-local",
-      "description": "Six-command context-engineering pipeline (brief → research → plan → execute → review → continue) with specialized agent swarms, external research triangulation, adversarial review, post-hoc independent review with Handover 6 feedback loop, multi-session resumption, session decomposition, and headless execution"
+      "name": "voyage",
+      "source": "./plugins/voyage",
+      "description": "Voyage — brief, research, plan, execute, review, continue. Contract-driven Claude Code pipeline with specialized agent swarms, external research triangulation, adversarial review, post-hoc independent review with Handover 6 feedback loop, multi-session resumption, session decomposition, and headless execution."
     },
     {
       "name": "linkedin-thought-leadership",