PR #666 introduced hardcoded SAFE_COMMAND_PREFIXES and SSRF URL
blocklists with no override mechanism. Users with non-standard
credential tools (sops, doppler, age, infisical) or needing to fetch
from internal URLs (self-hosted docs, VPN services) were silently
blocked with no recourse.
Add two global-only settings (ignored in project-level settings.json
to preserve the security property against malicious repos):
- allowedCommandPrefixes: replaces the built-in command allowlist
- fetchAllowedUrls: exempts hostnames from SSRF blocking
Both also support env var overrides (GSD_ALLOWED_COMMAND_PREFIXES,
GSD_FETCH_ALLOWED_URLS) for CI/container environments. Env vars
take precedence over settings.json.
Security model: global-only keys are stripped from project settings
at load time via stripGlobalOnlyKeys(), applied at all three
assignment points for this.projectSettings. The merge function
stays untouched — no future caller can accidentally skip stripping.
15 new tests covering override behavior, cache invalidation,
allowlist exemptions, and global-only enforcement.
