Sanitize MCP tool names and release 2.0.1

[arterialist]

What changed

• Sanitize LLM-facing MCP tool names to the OpenRouter-safe character set.
• Enforce a valid leading character, 64-character maximum, and deterministic uniqueness.
• Preserve original MCP names for tools/call routing.
• Always namespace duplicate server/tool names; remove the unsafe collision opt-out.
• Bump the package to 2.0.1 and document the behavior.

Why

MCP tool names can be valid under the MCP naming guidance while still being rejected by OpenRouter-backed providers. The previous collision flag also did not protect duplicate tool names: duplicate exposed names could overwrite the routing map. This keeps provider-facing names safe while retaining the raw server names for dispatch.

Verification

• Full test suite: 88 passed.
• Package build produced mcphero-2.0.1.tar.gz and mcphero-2.0.1-py3-none-any.whl.
• Ruff format checks passed for mcphero and tests.
• Ruff checks passed for the changed test files.
• Basedpyright passed on changed Python files with 0 errors, warnings, or notes.
• git diff --check passed.

The repository's full Ruff check still reports four pre-existing findings in unchanged lines of mcphero/adapters/base_adapter.py; they are outside this patch.