fix: interactive TUI should still show manage plugins/skills without being inside workspace folder

[christso]

Context

When I type allagents in a non-project workspace (a folder which does not have .allagents/workspace.yaml), i see a screen with "Initialize workspace" and don't see workspace status or manage plugins.

Proposal

Regardless of whether we're inside an allagents workspace or not:

The screen should have:

• Workspaces
• Marketplaces
• Plugins
• Skills

Then under workspaces, we have "Add workspace", "View status".
For marketplaces, that is already correct, as it as "Add marketplace" and choosing the marketplace provides options to update and remove.

For plugins and skills it should be the same, where we no longer need "manage" or "install" keyword and simply have the artifact name, and going in allows us to perform add/remove operations.

Ground Truth

Use agent-tui skill to understand current operation of the TUI and to validate your change was implemented correctly.

References

See example skill removal for npx skills remove. We want a similar flow when we disable skills.

christso@devbox-2:~/projects/allagents$ npx skills remove -g
│
◇  Found 17 unique installed skill(s)
│
◇  Select skills to remove (space to toggle)
│  agent-native-architecture, brainstorming, dispatching-parallel-agents, executing-plans, finishing-a-development-branch, receiving-code-review, requesting-code-review, subagent-driven-development, systematic-debugging, test-driven-development, using-git-worktrees,
using-superpowers, verification-before-completion, writing-plans, writing-skills
│
◇  Targeting 5 installed agent(s)
│
●  Skills to remove:
│
│    • agent-native-architecture
│
│    • brainstorming
│
│    • dispatching-parallel-agents
│
│    • executing-plans
│
│    • finishing-a-development-branch
│
│    • receiving-code-review
│
│    • requesting-code-review
│
│    • subagent-driven-development
│
│    • systematic-debugging
│
│    • test-driven-development
│
│    • using-git-worktrees
│
│    • using-superpowers
│
│    • verification-before-completion
│
│    • writing-plans
│
│    • writing-skills
│
◇  Are you sure you want to uninstall 15 skill(s)?
│  Yes
│
◇  Removal process complete
│
◆  Successfully removed 15 skill(s)
│
└  Done!

Closed by 2bbdf00