chore: add .opencode/dcp.jsonc with compress.protectTags enabled

[jflowers]

Problem

Slash command files use <protect> tags to mark execution-critical sections (guardrails, checklists, mandatory gates) that must survive DCP context compression. However, these tags are inert without a DCP config file that enables them.

Additionally, the replicator repo currently has "protectTags": true at the top level of opencode.json, which causes:

Configuration is invalid at opencode.json
↳ Unrecognized key: protectTags

Fix

1. Remove "protectTags": true from opencode.json
2. Add .opencode/dcp.jsonc to the repo with:

{
  "$schema": "https://raw.githubusercontent.com/Opencode-DCP/opencode-dynamic-context-pruning/master/dcp.schema.json",
  "compress": {
    "protectTags": true
  }
}

This file should be committed to source control (project-level setting, not personal config).

Context

• protectTags is a DCP plugin config key under compress, not an OpenCode core config key
• Placing it in opencode.json causes the startup error shown above
• The correct location is .opencode/dcp.jsonc (or dcp.json)
• Related: chore: add <protect> tags to slash command files for DCP context preservation unbound-force#497, chore(commands): add <protect> tags to slash command files unbound-force#499