[nightly-agent] Validate CLI and MCP agent surfaces

[r3dbars]

Summary

• Align TranscriptedCLI manifest validation with TranscriptedMCP by requiring manifest meeting/dictation paths to live under the declared capture library.
• Add CLI resolver coverage for ignoring incoherent mcp-directories.json manifests and falling back to default capture paths.

Verification

• cd Tools/TranscriptedCLI && swift build && swift test
• cd Tools/TranscriptedMCP && swift build -c release && swift test && ./.build/release/transcripted-mcp --self-test

Nightly surface check

• Confirmed docs for binary paths, env vars, and data-path defaults still match the CLI/MCP resolver code.
• Confirmed no other open [nightly-agent] draft existed before opening this PR.