fix(windows): use absolute path with shell:false for Claude spawn (#143)

On Windows, spawning Claude with shell: true causes the process to
exit immediately with code 1. This happens because shell: true invokes
cmd.exe /c claude <args>, and cmd.exe's PATH resolution differs from
direct process creation, leading to environment inconsistencies.

This fix:
- Adds findWindowsClaudePath() to locate claude.exe absolute path
- Changes spawn to use absolute path with shell: false on Windows
- Maintains Unix behavior (command name works fine with shell: false)
- Adds HAPI_CLAUDE_PATH env var for user override

Tested on Windows 11 with Claude Code v2.1.29 and hapi v0.15.0.

via [HAPI](https://hapi.run)

Co-authored-by: HAPI <noreply@hapi.run>

cli/src/claude/sdk/query.ts

@@ -347,8 +347,9 @@ export function query(config: {
         stdio: ['pipe', 'pipe', 'pipe'],
         signal: config.options?.abort,
         env: spawnEnv,
-        // Use shell on Windows for command resolution
-        shell: process.platform === 'win32'
+        // Use shell: false with absolute path from getDefaultClaudeCodePath()
+        // This avoids cmd.exe resolution issues on Windows
+        shell: false
     }) as ChildProcessWithoutNullStreams
 
     // Handle stdin