feat(cloudwatch-appsignals-mcp-server): add deprecation notices

[MichaelWalker-git]

Summary

• Add DEPRECATION_NOTICE constant and prepend to FastMCP instructions
• Add FutureWarning in main() to alert users at startup
• Add [DEPRECATED] prefix to all 13 tool docstrings (server.py, service_tools.py, slo_tools.py, trace_tools.py)
• Fix existing per-tool warnings: DeprecationWarning → FutureWarning, stacklevel=1 → stacklevel=2
• Update tests to handle new deprecation warning

This addresses the long-standing request from the ApplicationSignals team (since Dec 2025) to deprecate the old cloudwatch-appsignals-mcp-server in favor of cloudwatch-applicationsignals-mcp-server.

Test plan

• All 92 existing tests pass
• New test_main_emits_deprecation_warning verifies FutureWarning is emitted
• Ruff lint and format pass

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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.26%. Comparing base (c01ae71) to head (8f38a44).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2711      +/-   ##
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- Coverage   91.28%   91.26%   -0.02%     
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  Files        1015     1015              
  Lines       76261    76263       +2     
  Branches    12393    12393              
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- Hits        69612    69603       -9     
- Misses       4058     4065       +7     
- Partials     2591     2595       +4     

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[Copilot]

Pull request overview

This PR adds deprecation signaling to cloudwatch-appsignals-mcp-server to steer users toward the replacement cloudwatch-applicationsignals-mcp-server, using server-level instructions, startup warnings, and tool-level docstring labeling.

Changes:

• Introduces a shared DEPRECATION_NOTICE and surfaces it via FastMCP instructions plus a FutureWarning emitted at startup (main()).
• Prepends [DEPRECATED] to tool docstrings across the server and tool modules.
• Updates tests to tolerate/verify the new startup deprecation warning.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
src/cloudwatch-appsignals-mcp-server/awslabs/cloudwatch_appsignals_mcp_server/server.py	Adds DEPRECATION_NOTICE, surfaces it in FastMCP instructions, switches several warnings to FutureWarning, and emits a startup warning in main().
src/cloudwatch-appsignals-mcp-server/awslabs/cloudwatch_appsignals_mcp_server/service_tools.py	Marks service tools as [DEPRECATED] via docstrings.
src/cloudwatch-appsignals-mcp-server/awslabs/cloudwatch_appsignals_mcp_server/slo_tools.py	Marks SLO tools as [DEPRECATED] via docstrings.
src/cloudwatch-appsignals-mcp-server/awslabs/cloudwatch_appsignals_mcp_server/trace_tools.py	Marks trace tools as [DEPRECATED] via docstrings.
src/cloudwatch-appsignals-mcp-server/tests/test_server.py	Adjusts main() tests to ignore warnings and adds a new test asserting a deprecation FutureWarning is emitted.

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[MichaelWalker-git]

Closing — PR #2173 already merged and removed the cloudwatch-appsignals-mcp-server from main, making these deprecation notices moot. The server has been superseded by cloudwatch-applicationsignals-mcp-server.