fix(config): overlay cron command flag from system configs

[zezaeoh]

Summary

Adds cron.command_enabled to the DB-backed system_configs overlay so trusted deployments can enable deterministic command cron jobs without editing the base config file.

Type

• Feature
• Bug fix
• Hotfix (targeting main)
• Refactor
• Docs
• CI/CD

Target Branch

Targets dev.

Checklist

• go build ./... passes
• go build -tags sqliteonly ./... passes (if Go changes)
• go vet ./... passes
• Tests pass: go test -race ./...
• Web UI builds: cd ui/web && pnpm build (if UI changes)
• No hardcoded secrets or credentials
• SQL queries use parameterized $1, $2 (no string concat)
• New user-facing strings added to all 3 locales (en/vi/zh)
• Migration version bumped in internal/upgrade/version.go (if new migration)

Test Plan

• env -u GOCLAW_CONFIG -u GOCLAW_DATA_DIR -u GOCLAW_HOST -u GOCLAW_PORT -u GOCLAW_PUBLIC_URL -u GOCLAW_ALLOWED_ORIGINS PATH=/usr/local/go/bin:$PATH go test ./internal/config ./internal/gateway/methods ./internal/tools ./cmd
• env -u GOCLAW_CONFIG -u GOCLAW_DATA_DIR -u GOCLAW_HOST -u GOCLAW_PORT -u GOCLAW_PUBLIC_URL -u GOCLAW_ALLOWED_ORIGINS PATH=/usr/local/go/bin:$PATH go build ./...
• env -u GOCLAW_CONFIG -u GOCLAW_DATA_DIR -u GOCLAW_HOST -u GOCLAW_PORT -u GOCLAW_PUBLIC_URL -u GOCLAW_ALLOWED_ORIGINS PATH=/usr/local/go/bin:$PATH go build -tags sqliteonly ./...

[clark-cant]

LGTM — clean, minimal fix. Adds cron.command_enabled to the system_configs overlay with matching test coverage. Follows existing ApplySystemConfigs patterns (boolValue mapper, test assertion). No security or correctness concerns. CI go check still pending at review time; will re-check before merge. Reviewed by github-maintain automation.