feat: add VibrationAgent MCP server for vibration analysis benchmarks

[LGDiMaggio]

Summary

This PR adds a VibrationAgent MCP server to AssetOpsBench, introducing industrial vibration diagnostics capabilities as described in Issue #178.

What's included

Area	Files	Description
MCP Server	src/servers/vibration/main.py	8 MCP tools (FFT, envelope spectrum, ISO 10816, bearing frequencies, full diagnosis)
DSP Core	src/servers/vibration/dsp/	FFT analysis, envelope (Hilbert), bearing characteristic frequencies, fault detection
Data Layer	data_store.py, couchdb_client.py	In-memory signal store + CouchDB integration (reuses IoTAgent env vars)
Tests	src/servers/vibration/tests/	26 DSP unit tests + 17 MCP tool tests
Scenarios	vibration_utterance.json	20 benchmark scenarios (IDs 301-320)
Integration	pyproject.toml, executor.py, INSTRUCTIONS.md	scipy dep, entry point, DEFAULT_SERVER_PATHS registration, full docs

Tools provided

Tool	Description
get_vibration_data	Fetch vibration time-series from CouchDB
list_vibration_sensors	List available sensor fields for an asset
compute_fft_spectrum	FFT amplitude spectrum with top-N peaks
compute_envelope_spectrum	Envelope spectrum for bearing fault detection
assess_vibration_severity	ISO 10816 severity classification (Zones A-D)
calculate_bearing_frequencies	BPFO, BPFI, BSF, FTF computation
list_known_bearings	Built-in bearing database (9 designations)
diagnose_vibration	Full automated diagnostic pipeline with markdown report

Origin

DSP core adapted from vibration-analysis-mcp (Apache-2.0), with reliability fixes (kurtosis standardisation, velocity vectorisation, ddof consistency).

Testing

• 26/26 DSP tests pass (uv run pytest src/servers/vibration/tests/test_dsp.py -v)
• MCP tool tests (test_tools.py): blocked by Pydantic 2.12.5 + Python 3.14 incompatibility (repo-wide issue affecting all servers, not specific to this PR)

Notes

• Development assisted by GitHub Copilot (Claude)
• No breaking changes to existing servers or workflows

Ref #178

[florenzi002]

@LGDiMaggio I've seen the same issue with Pydantic in #187. That PR downgrades to 3.12 and the tests run just fine.

@ShuxinLin given this is a repo wide issue do you want a separate PR to fix versioning between python and pydantic versions (for visiblity) or are you happy with any of the incoming PRs to fix that?

[LGDiMaggio]

Thanks for the heads-up on #187 — good to know the 3.12 downgrade fixes it. Happy to align this PR with whatever versioning approach you settle on. Just let me know if any changes are needed on my side.

[ShuxinLin]

I downgraded the py version in this commit 8ef012c. It should be in main branch, no?

[LGDiMaggio]

Yes, 8ef012c is already in main — this PR branch is based on top of it.

I also just verified: after installing Python 3.12 via uv python install 3.12, all 42 vibration tests pass (26 DSP + 16 MCP tool tests), with 2 integration tests correctly skipped (no CouchDB).

======================== 42 passed, 2 skipped in 2.28s ========================

I'll push a small follow-up commit shortly to fix a minor test helper compatibility issue with fastmcp 2.14.5's call_tool return type.

[DhavalRepo18]

@LGDiMaggio, we will review this PR progressively.