fix(windows): resolve Claude binary path and apiKeyHelper shell syntax on Windows

[yakup-ozturk]

fix(windows): resolve Claude binary path and apiKeyHelper syntax on Windows:

Three changes that make ucode claude work on Windows without manual workarounds:

1. WinError 2 — Claude binary not found (agents/claude.py) Python's subprocess resolves PATH differently from cmd.exe and cannot find npm .cmd wrappers by name. Resolve CLAUDE_BINARY by walking from the claude.cmd wrapper to the actual claude.exe inside the npm package tree. Falls back to the wrapper path (or the bare "claude" string) if the .exe is absent, so non-Windows installs and non-standard npm layouts are unaffected.

2. apiKeyHelper shell syntax error on Windows (databricks.py) Claude Code runs the apiKeyHelper command via cmd.exe on Windows, which rejects the POSIX [ -n "$VAR" ] / env -u / jq syntax currently emitted by build_auth_shell_command. On os.name == 'nt' the function now returns a python -c "..." one-liner that handles the DATABRICKS_BEARER short- circuit and calls the Databricks CLI with subprocess, avoiding both the bash syntax and the jq dependency. POSIX behaviour is unchanged.

3. Settings not visible to the Claude desktop / IDE extension (agents/claude.py) ucode claude writes config to ~/.claude/ucode-settings.json and passes --settings when launching the CLI, but the Claude desktop app and IDE extensions read ~/.claude/settings.json by default. After writing the ucode-managed file, also merge the auth/env overlay into settings.json so the apiKeyHelper and ANTHROPIC_* vars are available in every launch path. A backup of the pre-existing settings.json is created alongside the existing ucode-settings backup.

Reference: https://medium.com/@Yakup-Ozturk/getting-claude-code-to-work-with-the-databricks-ai-gateway-on-windows-three-fixes-i-wish-i-knew-f6e71ece06a9