fix: route unknown-host machine unconstrained_delegation vulns to LLM exploit

[l50]

Key Changes:

• Prevent silent dropping of machine-account unconstrained delegation vulns when host IP is unknown
• Route unknown-host machine accounts to LLM exploit with distinct deduplication keys
• Ensure deterministic coerce chain is used only when machine host IP is known
• Added targeted tests to cover new fallback and host resolution logic

Added:

• LLM fallback routing for machine accounts without known host IPs, assigning a unique dedup key to avoid collisions and ensuring exploits are attempted
• Tests for unknown-host and known-host machine account scenarios, confirming correct fallback and host resolution behavior

Changed:

• Host IP resolution logic for machine accounts now distinguishes between known and unknown hosts, with explicit fallback handling
• Credentials and deduplication logic updated to support new fallback paths and avoid work item loss
• Self-coerce loop prevention applied only to deterministic coerce chain, bypassed for LLM fallback paths

Removed:

• Implicit dropping of machine-account unconstrained delegation vulns when host IP is missing, ensuring all valid work is surfaced

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.70%. Comparing base (1d559f3) to head (6fb1b70).
⚠️ Report is 1 commits behind head on feat/more-attack-cov.

Additional details and impacted files

@@                  Coverage Diff                  @@
##           feat/more-attack-cov     #314   +/-   ##
=====================================================
  Coverage                 77.69%   77.70%           
=====================================================
  Files                       439      439           
  Lines                    121368   121414   +46     
=====================================================
+ Hits                      94294    94340   +46     
  Misses                    27074    27074           

Files with missing lines	Coverage Δ
...s-cli/src/orchestrator/automation/unconstrained.rs	90.74% <100.00%> (+0.40%)	⬆️

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