[lesnik512]

Closes #451. Closes #460.

FastMCP HTTP metrics, tool metrics, and the scrape endpoint now use the configured Prometheus registry. The global registry remains the default. The optional in-progress gauge uses the configured registry and is shared across generated HTTP apps with matching gauge settings. The 2.x migration guide documents custom-registry scrapes.

The scheduled check exposed two test assumptions when FastMCP 4.2.0 added a __ prefix to hashed call names. Build aliases from FastMCP's call-name helper and assert the documented <hash>_<resolved tool name> metric label separately. Runtime metric labels and dependency requirements stay unchanged.

Verification with freshly upgraded dependencies on Python 3.14:

• Reproduced Scheduled dependency check failed #460: 2 failed and 3 passed in the focused hashed-tool cases on FastMCP 4.2.0. The original cases passed on 4.1.6.
• Corrected cases pass on both FastMCP 4.1.6 and 4.2.0: 5 passed each, including 100 proxy aliases sharing retained metric samples.
• Combined changes: 669 tests passed with 100% line coverage. Ruff, ty, EOF checks, and the strict docs build passed.
• Linux Python 3.11 FastMCP floor smoke passed with FastMCP 4.0.0, Instrumentator 8.0.1, and Sentry SDK 2.70.0.
• Fresh PR CI passed on c6878eca53235d1e43e469ce2ae3b26cb01a12e6, including Python 3.11–3.15, both free-threaded entries, all 23 configured floor entries, isolated extra installs, lint, links, and docs.
• Manual scheduled-workflow run passed on the same commit. This manual trigger also runs floors, which the daily scheduled trigger skips.
• Security audit passed.

Current resolved dependency versions include FastMCP/fastmcp-slim 4.2.0, MCP 2.3.0, Starlette 1.10.0, Instrumentator 8.1.0, and Sentry SDK 2.75.0.