feat(billing-cost-management): add Compute Optimizer get_idle_recomme…

[pputra]

…ndations and surface COH current resource details

Fixes

Summary

Changes

Two additive changes to the billing-cost-management-mcp-server, both around AWS Compute
Optimizer / Cost Optimization Hub:

1. compute-optimizer tool — new get_idle_recommendations operation. Wraps the Compute
   Optimizer GetIdleRecommendations
   API with server-side filtering by Finding (Idle / Unattached / Unused) and
   ResourceType. It reuses the same enrollment (ACTIVE) check and error handling as the
   existing recommendation operations. The formatted response includes resource ARN/ID/type,
   account ID, finding + finding description, both savings-opportunity variants (with and without
   discounts), utilization metrics, lookback period, last-refresh timestamp, tags, response-level
   errors, and the pagination token.

2. cost-optimization-hub get_recommendation — surface current_resource_details.
   Previously the formatted response included only recommended_resource_details; it now also
   includes current_resource_details.

Added unit tests for both changes (idle: basic call, filters/pagination, operation dispatch;
COH: current + recommended resource details) and a CHANGELOG entry. ruff check/ruff format
are clean.

User experience

Before

• The compute-optimizer tool exposed only performance/right-sizing operations — there was no way
  to retrieve Compute Optimizer idle recommendations or to filter by resource state
  (idle / unattached / unused).
• cost-optimization-hub get_recommendation returned only the recommended resource details.

After

• Users can call compute-optimizer with operation="get_idle_recommendations" and filter by
  Finding and ResourceType to get idle-resource recommendations directly
• cost-optimization-hub get_recommendation returns current_resource_details alongside
  recommended_resource_details, so current resource state is available.

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Is this a breaking change? (Y/N) N

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

[codecov]

Codecov Report

❌ Patch coverage is 96.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 93.22%. Comparing base (5609db9) to head (9fb7d65).

Files with missing lines	Patch %	Lines
...gement_mcp_server/tools/compute_optimizer_tools.py	95.65%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4551   +/-   ##
=======================================
  Coverage   93.22%   93.22%           
=======================================
  Files        1046     1046           
  Lines       88477    88502   +25     
  Branches    14293    14301    +8     
=======================================
+ Hits        82482    82510   +28     
+ Misses       3623     3622    -1     
+ Partials     2372     2370    -2     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.