fix(plugin): update project-scoped marketplaces

[christso]

Summary

Project-scoped marketplace plugins can now be updated through both the headless CLI and interactive TUI. Previously, project marketplace add, list, install, and sync all worked, but plugin update --scope project searched only the user registry and failed with Marketplace not found.

Update targets now retain their installation scope through marketplace lookup, refresh, and deduplication. User updates remain user-registry-only, project updates use the workspace registry with project-over-user precedence, and --scope all updates the same plugin independently when it is installed in both scopes.

Related: #224

Validation

The regression suite exercises project-only, user-only, and identical user + project installations using local network-free marketplaces:

bun test tests/e2e/plugin-update.test.ts
bun test
bun run typecheck
bun run lint
bun run build

• Focused: 3 passed, 0 failed.
• Full suite: 1,350 passed, 5 skipped, 0 failed.
• Independent review found a cross-scope deduplication gap; the added --scope all regression was confirmed red before the fix and green afterward.

Manual WTG.AI.Prompts validation used the built CLI with an isolated user registry:

WORKTREE=/home/entity/projects/EntityProcess/allagents.worktrees/fix-project-marketplace-update
CLI="$WORKTREE/dist/index.js"
WTG=/home/entity/projects/WiseTechGlobal/WTG.AI.Prompts
PROJECT=$(mktemp -d /tmp/allagents-marketplace-update.XXXXXX)

git init "$PROJECT"
"$CLI" init "$PROJECT" --client copilot

cd "$PROJECT"
ALLAGENTS_TEST_HOME="$PROJECT/home" "$CLI" plugin marketplace add "$WTG" --scope project
ALLAGENTS_TEST_HOME="$PROJECT/home" "$CLI" plugin install org@wtg-ai-prompts --scope project
ALLAGENTS_TEST_HOME="$PROJECT/home" "$CLI" plugin update org@wtg-ai-prompts --scope project

The final update completed with one plugin updated, zero skipped, zero failed, and the project workspace resynced successfully.

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