fix(cosh): add skill_context to PreToolUse hook input for resolved skill path

[samchu-zsl]

Summary

• Adds skill_context (with skill_name and file_path) to PreToolUseInput, symmetric with existing mcp_context for MCP tools
• When the Skill tool fires PreToolUse, coreToolScheduler now resolves the skill via SkillManager and attaches the resolved path to the hook input
• Hooks can now locate skill directories on disk even when the SKILL.md name differs from the directory name

Type of Change

• Bug fix

Related Issue

Closes #381

Testing

cd src/copilot-shell
npm run build && npm run test && npm run lint && npm run typecheck
# 125 hook tests passed, build succeeded, lint clean, typecheck clean

Changed Files

File	Change
hooks/types.ts	Add SkillToolContext interface and skill_context? field to PreToolUseInput
hooks/hookEventHandler.ts	Forward optional skillContext parameter
hooks/hookSystem.ts	Forward optional skillContext parameter in facade
core/coreToolScheduler.ts	Resolve skill path before PreToolUse hook fire
tools/skill.ts	Add resolveSkillConfig() method to SkillTool
hooks/hookEventHandler.test.ts	2 new tests for skill_context inclusion/omission

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[samchu-zsl]

Manually tested the PreToolUse hook by:

1. Creating ~/.copilot-shell/hooks/dump-pretooluse.sh:

#!/bin/bash
cat > /tmp/pretooluse-hook-dump.json

2. Adding to ~/.copilot-shell/settings.json:

"hooks": {
  "PreToolUse": [{
    "matcher": "Skill",
    "hooks": [{
      "type": "command",
      "command": "bash ~/.copilot-shell/hooks/dump-pretooluse.sh",
      "name": "dump-pretooluse"
    }]
  }]
}

3. Running /skills in cosh, then verifying output:

> cat /tmp/pretooluse-hook-dump.json | jq
{
  "session_id": "b9d9c537-aca1-4b6d-a380-c64abe36b7e6",
  "transcript_path": "xxx/b9d9c537-aca1-4b6d-a380-c64abe36b7e6.jsonl",
  "cwd": "xxx/copilot-shell",
  "hook_event_name": "PreToolUse",
  "timestamp": "2026-04-28T11:23:15.485Z",
  "tool_name": "skill",
  "tool_input": { "skill": "uv-package-manager" },
  "skill_context": {
    "skill_name": "uv-package-manager",
    "file_path": "xxx/skills/uv-package-manager/SKILL.md"
  }
}

[1570005763]

LGTM.

[kongche-jbw]

lgtm，thx