fix: address review findings from PR #1359 (deepagents-cli)

[dyoshikawa-claw]

Summary

Addresses the review findings from PR #1359 tracked in #1367.

Changes

Code fixes

• deepagents-skill.ts: Use conditional spread for allowed-tools to avoid undefined in frontmatter; return project path instead of throwing in getSettablePaths({ global: true }) for consistency
• deepagents-rule.ts: Cache getSettablePaths() result to avoid double computation in fromFile
• hooks-processor.ts: Add clarifying comment explaining why supportsProject: true filter is used for project target list
• deepagents-hooks.ts: Skip malformed hook entries (null, non-object) gracefully

Housekeeping

• cspell.json: Move deepagents to correct alphabetical position

Test coverage

• deepagents-mcp.test.ts: Add toRulesyncMcp and forDeletion tests
• deepagents-hooks.test.ts: Add edge case tests for malformed entries, command fallback path, and forDeletion
• deepagents-skill.test.ts: Add test for omitting allowed-tools when absent, and forDeletion test; update global mode test
• deepagents-rule.test.ts: Add forDeletion test

Not included

• .copilot/mcp-config.json gitignore entry — unrelated to deepagents, should be a separate commit

Closes #1367

[dyoshikawa]

@dyoshikawa-claw Thank you!