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.

plugins/ultraplan-local/.gitignore

@@ -1,25 +0,0 @@
-# OS files
-.DS_Store
-Thumbs.db
-Desktop.ini
-
-# Editor files
-*.swp
-*.swo
-*~
-.vscode/
-.idea/
-
-# Local configuration / session files
-*.local.*
-REMEMBER.md
-TODO.md
-ROADMAP.md
-
-# Local planning docs (briefs, design notes, observations) — never committed.
-# Existing tracked files in docs/ predate this rule; new planning docs stay local.
-docs/ultracontinue-brief.md
-docs/ultracontinue-design-notes.md
-
-# Ultraplan project directories — briefs, research, plans, progress all local.
-.claude/projects/