chore: goose2 skill refactor

[lifeizhou-ap]

Summary

Refactor the Skills feature for better separation of concerns. No user-facing behavior changes, except clearer error feedback via toasts.

Changes

Extractions

• hooks/useSkillImportExport.ts — extracts import/export logic (file picker, drop zone, toast feedback) out of SkillsView.
  • Why: SkillsView had a duplicated import flow (button vs. drag-and-drop) and an inline export handler. The hook collapses these into one reusable surface.
• lib/skillsPath.ts — moves path helpers (basename, normalizePath, getSkillFileLocation, deriveProjectRoot, getRenamedSkillFileLocation) out of api/skills.ts and CreateSkillDialog.
  • Why: path logic was duplicated across layers; co-locating it makes it testable and prevents drift.
• lib/skillsHelpers.ts — filterSkills and groupSkills extracted from SkillsView's useMemo blocks; isValidSkillName and formatSkillName moved here from CreateSkillDialog.
  • Why: pulls pure functions out of the view so SkillsView becomes a thin orchestrator and the rules are unit-testable.
• ui/SkillsToolbar.tsx and ui/SkillCategoryFilter.tsx — search bar, filter row, and category dropdown lifted out of SkillsView.
  • Why: self-contained UI blocks with their own props; inlining them bloated the parent without benefit.

Renames

• CreateSkillDialog → SkillEditor (and matching test file).
  • Why: the component already handled both create and edit modes; the old name was misleading.

Type cleanup on SkillInfo

• Removed directoryPath — was always assigned source.directory, identical to path.
• Removed editable — was hardcoded to true, so the skill.editable ? … : null gates around Edit and Delete were dead conditionals. Simplified to unconditional rendering.
• Added EditingSkill = Pick<SkillInfo, …> so SkillEditor and SkillsDialogs share a single type instead of redeclaring the same five fields inline.
• Why: removes dead fields and stops three files from drifting on the same shape.

User-facing feedback: custom notification → toast

• Replaced the bottom-right notification div (export-only, 3-second timeout, manually managed) with sonner toasts.
• Added toasts for previously silent failures: load error, import success and error, delete success and error.
• Why: the old notification was export-only; other failures logged to the console and the user saw nothing. Toasts give consistent feedback and remove a piece of bespoke UI.

i18n

• Added loadError, importSuccess, importError, exportError, deleteSuccess, deleteError in en and es.

Net effect

• SkillsView.tsx: 325 → 55 lines (orchestration only).
• No user-visible regressions; users now get toast feedback on operations that previously failed silently.