[BUG] Plugins with version "1.0.0" are never auto-updated despite marketplace repo changes

Description

Some official plugins are installed with a fixed version: "1.0.0" string instead of a git commit hash. These plugins are never auto-updated, even when the marketplace repository has newer commits. Other plugins from the same marketplace correctly receive commit-hash versions (e.g., 9dca34150caa) and update normally.

Affected Plugins (all from claude-plugins-official)

| Plugin | version | lastUpdated | Auto-updates? |
|--------|---------|-------------|---------------|
| pyright-lsp | 1.0.0 | 2026-03-03 (28d) | No |
| typescript-lsp | 1.0.0 | 2026-03-17 (14d) | No |
| claude-md-management | 1.0.0 | 2026-03-17 (14d) | No |
| claude-code-setup | 1.0.0 | 2026-03-17 (14d) | No |
| github | 9dca34150caa | 2026-03-28 (3d) | Yes ✓ |
| hookify | 9dca34150caa | 2026-03-28 (3d) | Yes ✓ |
| skill-creator | 9dca34150caa | 2026-03-28 (3d) | Yes ✓ |

Steps to Reproduce

1. Install all official plugins from claude-plugins-official marketplace
2. Wait for auto-update cycle (or restart Claude Code)
3. Check ~/.claude/plugins/installed_plugins.json
4. Observe: some plugins have "version": "1.0.0", others have commit hashes
5. The 1.0.0 plugins' cache directory is named 1.0.0/ instead of a commit hash
6. Delete the 1.0.0/ cache directory and restart — plugin is reinstalled but again with version: "1.0.0"

Root Cause Hypothesis

The affected plugins do not have a manifest.json in their plugin directory within the marketplace repo. Plugins without manifest.json appear to default to version: "1.0.0". Since the version string never changes, the auto-update mechanism sees "1.0.0 == 1.0.0" and skips the update, even though the underlying plugin files have changed in the repo.

Plugins that DO auto-update correctly receive the git commit hash as their version, which changes with every repo update.

Expected Behavior

All plugins from the same marketplace should be updated when the marketplace repo has new commits, regardless of whether they have a manifest.json with an explicit version field.

Environment

• Claude Code v2.1.88
• OS: Linux (WSL2)
• Marketplace: claude-plugins-official