Merge origin/master into skill system branch

Use the new filesystem seam for skill file reads and system skill writes when ctx.fs is available, and include the skill tool in the generated tool catalog.

packages/core/skill/tests/skill.spec.ts

@@ -4,6 +4,7 @@ import { join } from 'node:path'
 import { tmpdir } from 'node:os'
 import { Context } from 'cordis'
 import SkillService from '@deepseek-ai/dsh-skill'
+import LocalFileSystem from '@deepseek-ai/dsh-fs-local'
 
 async function tempDir(name: string): Promise<string> {
   return await import('node:fs/promises').then(fs => fs.mkdtemp(join(tmpdir(), `dsh-${name}-`)))
@@ -194,6 +195,24 @@ describe('SkillService', () => {
     expect(await readFile(join(home, '.dsh/skills/.system/dsh-skill-creator/SKILL.md'), 'utf8')).toContain('dsh-skill-creator')
   })
 
+  it('uses the filesystem service when installing bundled system skills', async () => {
+    const home = await tempDir('skill-install-fs')
+    const existing = join(home, '.dsh/skills/.system/dsh-plugin-creator/SKILL.md')
+    await mkdir(join(home, '.dsh/skills/.system/dsh-plugin-creator'), { recursive: true })
+    await writeFile(existing, '---\nname: dsh-plugin-creator\ndescription: Existing system skill\n---\n\nExisting body.\n')
+
+    const ctx = new Context()
+    await ctx.plugin(LocalFileSystem, { cwd: home })
+    await ctx.plugin(SkillService, { dshHome: join(home, '.dsh'), agentsHome: join(home, '.agents') })
+
+    expect((await ctx.skills.list()).map(skill => [skill.name, skill.description])).toEqual([
+      ['dsh-plugin-creator', 'Existing system skill'],
+      ['dsh-skill-creator', 'Create or update DeepSeek Harness SKILL.md instructions.'],
+    ])
+    expect(await readFile(existing, 'utf8')).toContain('Existing body.')
+    expect(await readFile(join(home, '.dsh/skills/.system/dsh-skill-creator/SKILL.md'), 'utf8')).toContain('dsh-skill-creator')
+  })
+
   it('renders bundled system skill files with and without routing metadata', async () => {
     const home = await tempDir('skill-install-render')
 
@@ -205,6 +224,26 @@ describe('SkillService', () => {
     expect(await readFile(join(home, '.dsh/skills/.system/dsh-skill-creator/SKILL.md'), 'utf8')).toContain('whenToUse:')
   })
 
+  it('uses the filesystem service for skill file reads when it is available', async () => {
+    const home = await tempDir('skill-read-fs')
+    const root = join(home, '.dsh/skills')
+    await writeFlatSkill(root, 'text-skill', 'Text skill', 'Text body.')
+    await mkdir(join(root, 'empty-dir'), { recursive: true })
+    await mkdir(join(root, 'directory-skill/SKILL.md'), { recursive: true })
+    await writeFile(join(root, 'binary-skill.md'), Buffer.concat([
+      Buffer.from('---\nname: binary-skill\ndescription: Binary skill\n---\n\n'),
+      Buffer.from([0xff]),
+      Buffer.from('\n'),
+    ]))
+
+    const ctx = new Context()
+    await ctx.plugin(LocalFileSystem, { cwd: home })
+    await ctx.plugin(SkillService, { dshHome: join(home, '.dsh'), agentsHome: join(home, '.agents'), installSystemSkills: false })
+
+    expect((await ctx.skills.list()).map(skill => skill.name)).toEqual(['text-skill'])
+    expect(await ctx.skills.get('binary-skill')).toBeUndefined()
+  })
+
   it('degrades when bundled system skill installation fails', async () => {
     const home = await tempDir('skill-install-fail')
     await writeFile(join(home, '.dsh'), 'not a directory')