[BUG] Plugin subagent namespace prefix stripped when launching subagent

Bug Description

When a plugin-provided subagent (e.g., from everything-claude-code:code-reviewer) is spawned, the metadata correctly stores the fully-qualified agent type, but when the system attempts to launch/restore the subagent, it incorrectly strips the namespace prefix and looks for a non-existent bare agent type.

Steps to Reproduce

1. Install everything-claude-code plugin
2. Trigger a code review (e.g., through auto-invocation or manual trigger)
3. Observe the subagent creation:

• Metadata stores: "agentType":"everything-claude-code:code-reviewer" ✓
• System tries to launch: "code-reviewer" (namespace stripped) ✗

Expected Behavior

The subagent should be launched using the fully-qualified agent type (everything-claude-code:code-reviewer) as stored in the metadata.

Actual Behavior

● code-reviewer(Review multi-folio PMS changes)
  ⎿  Initializing…
  ⎿  Error: Agent type 'code-reviewer' not found. Available agents: general-purpose, statusline-setup, Explore, Plan, ...

Root Cause

The OpenCode framework defines agents with short names ("code-reviewer" in .opencode/opencode.json), but the Claude Code agent system requires fully-qualified names ("everything-claude-code:code-reviewer"). There's a mismatch in how the subagent orchestration layer resolves plugin-provided agent types.

Environment

• Claude Code version: Latest (2026-04-17)
• Plugin: everything-claude-code@everything-claude-code (enabled)
• Affected agent types: All plugin-provided subagents (code-reviewer, go-reviewer, python-reviewer, etc.)

Workaround

Manually invoke code review using the correct agent type:

• everything-claude-code:code-reviewer for immediate code quality review
• superpowers:code-reviewer for plan compliance review

Additional Context

Metadata file content:

{"agentType":"everything-claude-code:code-reviewer","description":"Review multi-folio PMS changes"}

The metadata is correct, but the launch logic strips the namespace prefix.