docs: add 5.2.0 changelog

[tomaz-lc]

Details

Add changelog entry for the 5.2.0 release covering PRs #257, #260, #261, #262, #263.

Included changes

• Lazy command loading (feat: lazy command loading for faster CLI startup #261) - 52-67% faster CLI startup via on-demand module loading, plus __version__ fix
• Consolidated config directory (feat: consolidate config files into ~/.limacharlie.d/ directory #257) - Unified ~/.limacharlie.d/ layout with migration tooling
• Summary on case create (feat: add summary parameter to case create #262) - New --summary flag for case create
• Help topic name matching (fix: match help topic names to CLI command names #263) - Singular/plural fallback for help topics
• Shell completion docs (docs: add shell completion setup instructions to README #260) - README instructions for bash/zsh/fish tab-completion
• CI improvements (feat: lazy command loading for faster CLI startup #261) - Version consistency checks and PyPI stable sanity check

Blast radius / isolation

CHANGELOG.md only - no code changes.

Performance characteristics

No impact.

Notable contracts / APIs

None.

Related PRs

• feat: consolidate config files into ~/.limacharlie.d/ directory #257 - Consolidate config files into ~/.limacharlie.d/
• docs: add shell completion setup instructions to README #260 - Shell completion setup instructions
• feat: lazy command loading for faster CLI startup #261 - Lazy command loading for faster CLI startup
• feat: add summary parameter to case create #262 - Add summary parameter to case create
• fix: match help topic names to CLI command names #263 - Match help topic names to CLI command names