docs: update WorldCup2026 README to remove stale sections

[TimWheeler-SQUP]

Updates ReadMe to be clearer and remove incorrect information.

[clarkd]

Claude might flag a version bump here, but not needed given it's just README changes

[clarkd]

@claude review once

[github-actions]

🧩 Plugin PR Summary

📦 Modified Plugins

• plugins/WorldCup2026/v1

📋 Results

Step	Status
Validation	✅ Passed
Deployment	🚀 Deployed

🔍 Validation Details

✅ worldcup2026

{
  "valid": true,
  "pluginName": "worldcup2026",
  "pluginType": "hybrid",
  "summary": {
    "Data Streams": 7,
    "Import Definitions": 1,
    "UI Configuration": false,
    "Has Icon": true,
    "Has Default Content": true,
    "Config Validation": true,
    "Custom Types": true
  }
}

[claude]

Version bump added as requested — docs-only change is good to merge.

Extended reasoning...

Overview

This PR removes three stale sections ("What gets indexed", "Configuration", "Known limitations") from the WorldCup2026 plugin README and bumps the plugin version from 1.2.0 to 1.2.1. Two files changed: plugins/WorldCup2026/v1/docs/README.md and plugins/WorldCup2026/v1/metadata.json.

Security risks

None. This is a documentation-only change plus a version string update. No code, credentials, network behavior, or auth surfaces are touched.

Level of scrutiny

Minimal. Docs-only deletion of stale content with the required patch version bump per repo policy. The plugin uses authMode: none and has no UI configuration, so the removed "Configuration" section was indeed accurate to remove.

Other factors

My prior review on this PR flagged the missing version bump; the author has addressed it (1.2.0 → 1.2.1, appropriate patch bump for a docs change). No outstanding reviewer comments remain. The bug hunting system found no issues.