[FEATURE] Move MCP out of tools package

[mkmeral]

Problem Statement

MCP as a concept is bigger than tools now as it includes prompts, resources, tasks, elicitation, and more.

Reviewing this PR, I have realized MCP is still under tools module.

Proposed Solution

We should move MCP out of tools module, and add an alias back to tools for backwards compatibility.

Use Case

N/A

Alternatives Solutions

No response

Additional Context

No response

[fede-kamel]

Addressing via a 3-PR stack, each independently reviewable and mergeable:

• feat(mcp): add strands.mcp as canonical MCP import path (1/3) #2148 (1/3) — strands.mcp as re-export of strands.tools.mcp. Additive only.
• feat(mcp): move MCP implementation to strands.mcp, deprecate old path (2/3) #2152 (2/3) — move implementation; strands.tools.mcp becomes a sys.modules-based deprecation alias.
• feat(mcp): move MCP tests + update integ imports + docs (3/3) #2158 (3/3) — tests, integ tests, README, AGENTS.md.

Full strategy, design decisions, and test evidence live in each PR's description. Backwards compatibility verified end-to-end against tests_integ/mcp/echo_server.py, the public awslabs.aws-documentation-mcp-server MCP server, and Agent+MCP flows with a real LLM.