🛡️ Sentinel: [HIGH] Fix SSRF in CLI executor

[rschumann]

🚨 Severity: HIGH
💡 Vulnerability: Unvalidated remoteHost used to construct HTTP request to the bridge agent in executeRemote, causing SSRF.
🎯 Impact: An attacker or malicious user could potentially forge the remote host value, forcing the gateway to make HTTP requests to internal networks or malicious resources.
🔧 Fix: Introduced URL parsing via net/url to explicitly validate that the requested scheme is http or https.
✅ Verification: Verified via gosec scan and tested all package tests locally using go test ./... -short.

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PR created automatically by Jules for task 5129941960299805927 started by @rschumann

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