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/tests/fixtures/plan-fase-narrative.md

@@ -1,25 +0,0 @@
-# Bad plan — narrative drift fixture
-
-plan_version: 1.7
-
-This fixture exists ONLY to verify that `plan-validator --strict`
-rejects Opus 4.7-style narrative drift (Fase / Phase / Stage / Steg
-headings instead of `### Step N:`). It MUST FAIL strict validation.
-
-## Context
-
-This is what an LLM might produce when it ignores the literal-step
-schema and falls back to narrative phasing. The validator should
-catch this and refuse.
-
-### Fase 1: Forberedelse
-
-Vi må først forstå koden. Les filene under src/.
-
-### Fase 2: Implementering
-
-Skriv ny kode i nye filer.
-
-### Fase 3: Verifisering
-
-Kjør testene og fiks eventuelle feil.