[codex] Handle Claude plugin config token env names

[hammadtq]

Summary

This fixes the plugin token handoff for Claude Code plugin installs by accepting the manifest key form that Claude documents for userConfig environment variables.

What Changed

• accept CLAUDE_PLUGIN_OPTION_socket_api_token in plugin/hooks/bootstrap.sh
• keep the existing uppercase CLAUDE_PLUGIN_OPTION_SOCKET_API_TOKEN path as a compatibility fallback
• add plugin tests that execute the bootstrap wrapper and verify both env var names map into SOCKET_API_TOKEN
• clarify the README so the token prompt is described as an install/enable flow, and note that local claude --plugin-dir ./plugin development may require manually exporting SOCKET_API_TOKEN

Root Cause

The plugin manifest key is socket_api_token, but the bootstrap wrapper only checked the fully uppercased env var name. If Claude exposes the config using the documented <KEY> form without uppercasing, the wrapper misses the token and hard-fails even though the user supplied it.

Validation

• go test ./plugin
• go test ./...
• go vet ./...
• go build ./...
• env -u SOCKET_API_TOKEN CLAUDE_PLUGIN_OPTION_socket_api_token=test-token plugin/hooks/bootstrap.sh version

[hammadtq]

LGTM