feature(manual-test-planning): categorize plans with more than five tests

[mxriverlynn]

What this changes

The manual-test-planning skill now looks for a plain-language way to categorize the tests whenever a plan holds more than five of them. When a natural grouping covers every test, both Tests at a Glance and Test Details are organized under the category names, with the same categories and test order in both sections. When no grouping covers every test, or the plan has five tests or fewer, the flat list stays.

Files changed

• han-coding/skills/manual-test-planning/SKILL.md — Step 3 gains the categorization rule (threshold, one category per test, plain-language names, run order preserved, flat-list fallback); Step 4 tells the draft to follow the template's categorized layout; Step 7 preserves category names through the readability edit and adds a self-check that both sections still share the same category structure; the frontmatter description mentions the category behavior.
• han-coding/skills/manual-test-planning/references/template.md — Tests at a Glance and Test Details each document the flat and categorized layouts (categories as level-three headings, tests as level-four headings in the details).
• han-coding/docs/skills/manual-test-planning.md — long-form doc updated to match: key concepts, what you get back, and the step walkthrough.

Notes

• No version bump; versioning is left to the release process.
• Scent lines in the plugin README and skills index are unchanged; the category behavior is a detail below the one-sentence scent.