Avoid widening incompatible ParamSpec constraints

[MestreY0d4-Uninter]

Refs #21384.

Summary

This avoids widening incompatible precise ParamSpec lower-bound constraints to Any when solving constraints. In the protocol case from #21384, different protocol members can infer conflicting concrete parameter lists; joining those currently erases the conflict and lets invalid calls through.

The PR keeps imprecise ParamSpec argument constraints on the existing path, and only rejects incompatible precise Parameters constraints.

This addresses the free-function and wrapper-argument paths from the issue. The direct generic self-call form still needs separate handling.

Test Plan

• PYTHONPATH=. uv run --no-project --isolated --with-requirements test-requirements.txt python -m pytest -q mypy/test/testcheck.py::TypeCheckSuite::check-parameter-specification.test mypy/test/testsolve.py
• PYTHONPATH=. uv run --no-project --isolated --with-requirements test-requirements.txt python -m mypy --config-file mypy_self_check.ini mypy/solve.py
• git diff --check

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pwndbg (https://github.com/pwndbg/pwndbg)
+ pwndbg/commands/onegadget.py:26: error: Cannot infer function type argument  [misc]
+ pwndbg/commands/cpsr.py:18: error: Cannot infer function type argument  [misc]

antidote (https://github.com/Finistere/antidote)
+ src/antidote/core/_inject.py:293: error: Cannot infer value of type parameter "_P" of "staticmethod"  [misc]

discord.py (https://github.com/Rapptz/discord.py)
- discord/ext/commands/core.py:672: error: Unused "type: ignore" comment  [unused-ignore]