test: Pin mcp<2 for fastmcp<0.3

[alexander-alderman-webb]

Description

Old fastmcp package versions are incompatible with mcp v2.

Stack traces are as follows:

tests/integrations/fastmcp/test_fastmcp.py:847: in test_fastmcp_prompt_sync
    mcp = FastMCP("Test Server")
          ^^^^^^^^^^^^^^^^^^^^^^
.tox/py3.14-fastmcp-v0.1.0/lib/python3.14/site-packages/fastmcp/server.py:61: in __init__
    self._setup_handlers()
.tox/py3.14-fastmcp-v0.1.0/lib/python3.14/site-packages/fastmcp/server.py:85: in _setup_handlers
    self._mcp_server.list_tools()(self.list_tools)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   AttributeError: 'Server' object has no attribute 'list_tools'

Issues

Closes #6906

Reminders

• Please add tests to validate your changes, and lint your code using uv run ruff.
• Add GH Issue ID & Linear ID (if applicable)
• PR title should use conventional commit style (feat:, fix:, ref:, meta:)
• For external contributors: CONTRIBUTING.md, Sentry SDK development docs, Discord community

[github-actions]

Codecov Results 📊

✅ 98668 passed | ⏭️ 6781 skipped | Total: 105449 | Pass Rate: 93.57% | Execution Time: 356m 57s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +135
Passed Tests	📈 +110
Failed Tests	—
Skipped Tests	📈 +25

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2498 uncovered lines.
✅ Project coverage is 89.84%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    89.84%    89.84%        —%
==========================================
  Files          193       193         —
  Lines        24588     24587        -1
  Branches      8744      8744         —
==========================================
+ Hits         22089     22089         —
- Misses        2499      2498        -1
- Partials      1400      1399        -1

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