test(mcp): add Redis Stack-backed integration coverage for Redis JSON/Search/Bulk/Aliases

[joshrotenberg]

Summary

The Redis MCP surface now depends on module-specific commands that plain Redis does not provide:

• RedisJSON
• RediSearch
• bulk/seed workflows that benefit from Stack-backed verification
• session-scoped alias tools that should be exercised in the same Docker-backed suite

We should add a Redis Stack-backed ignored integration suite alongside the existing plain Redis Docker suite so the module-heavy Redis MCP tools are validated against a real server, not just compile/build checks.

Why

The existing plain Redis suite is a good fit for:

• server
• keys
• structures
• diagnostics
• raw command safety/policy

But it cannot validate:

• redis_json_*
• redis_ft_*
• redis_bulk_load with module commands
• alias workflows combined with real Redis operations

Proposed work

• Add shared Redis MCP test support so plain Redis and Redis Stack containers use the same harness patterns
• Add a Redis Stack-backed ignored suite under crates/redisctl-mcp/tests/
• Cover the missing Redis MCP modules:
  • JSON
  • Search
  • Bulk/seed
  • Aliases
• Make reruns stable with container reuse / reattach behavior so Docker-backed tests do not fail on healthy leftover containers

Acceptance criteria

• Redis Stack-backed ignored test suite exists and is documented
• JSON/Search/Bulk/Alias MCP tools are exercised against a real Redis Stack container
• Test harness is reusable across Redis MCP integration suites
• Rerunning ignored suites does not fail just because a healthy test container already exists

Context

Related to #628 and #681.