feat: add support for reading skills from `.agents/skills`

[karlhorky]

What would you like to be added?

Support the .agents/skills (.agents with an s)

Currently, only .agent/skills (.agent WITHOUT an s) was implemented: (another PR:

• first PR by @DragonnZhang and approved by @tanzhenxin
  • feat(core): add symlink support for skill manager #1690
• second PR by @LaZzyMan and approved by @tanzhenxin
  • feat: support skills in .agents directory and other provider directories #2202

This should probably be renamed:

• current: .agent/skills
• new: .agents/skills

cc @douglascamata

Why is this needed?

This is becoming a standard with a lot of AI agent software:

• Proposal: include a standard folder where agent skills should be agentskills/agentskills#15

Additional context

No response

[DragonnZhang]

See #2086

[Br1an67]

I've traced through the code and this is a one-line fix. The skill provider directories are defined in a single constant:

// packages/core/src/config/storage.ts, line 15
export const SKILL_PROVIDER_CONFIG_DIRS = ['.qwen', '.agent'];

All skill loading code (skill-manager.ts, storage.ts getUserSkillsDirs()) reads from this array, so adding .agents to the array propagates everywhere automatically. I have a PR ready.