Skip mainnet RPC probe when mainnet is explicitly disabled

[MysticRyuujin]

Summary

Closes #22.

Adds a skipMainnetProbe: false field to the [general] section of config.yaml. When true, install.Configured() skips the mainnet RPC reachability probe and the wizard no longer rejects mainnet.enabled: false. This unblocks headless / air-gapped / container / CI deployments — specifically, the kurtosis ethereum-package integration that runs khedra against an isolated devnet with no public network access.

Default is false, so existing installs are completely unaffected.

Design (revised per maintainer feedback)

The first version of this PR detected the headless case with a second-pass YAML unmarshal into a *bool. As @tjayrush pointed out, that created a hidden three-state boolean — two identical Chain structs could exhibit different runtime behavior depending on whether enabled was omitted or explicitly false. Fragile and surprising.

This revision replaces that with a plain bool in the [general] section, exactly as suggested. No YAML sniffing, no ambiguity, no helper functions.

How it works

pkg/types/general.go

• New field SkipMainnetProbe bool with koanf / yaml / json tags. No validate tag needed for a plain bool.

pkg/types/config.go

• Template emits skipMainnetProbe: {{ .General.SkipMainnetProbe }} under the general: block.

pkg/types/apply_env.go

• New env key KeyGeneralSkipMainnetProbe = "TB_KHEDRA_GENERAL_SKIPMAINNETPROBE" with a strconv.ParseBool handler.

pkg/install/validity.go

• Configured() calls checkMainnetAccessible() unless cfg.General.SkipMainnetProbe is true.
• Structural checks (RPC non-empty, chainId != 0) still run unconditionally, so downstream code that reads main.RPCs[0] (env wiring in action_daemon.go) stays safe.

pkg/install/validation.go

• ValidateChains continues to emit require_mainnet when mainnet.enabled: false unless general.skipMainnetProbe: true. Error message updated to mention the escape hatch.

Docs

• config.yaml.example — field added with explanatory note.
• book/src/user_manual/getting_started.md — reference config + note 7 (with kurtosis link and env-var override).

Test plan

• go build ./... clean
• go test ./pkg/install/... ./pkg/types/... passes — includes:
  • TestConfigured_SkipMainnetProbe_SkipsReachabilityProbe
  • TestConfigured_SkipMainnetProbeOmitted_RequiresReachableProbe
  • TestConfigured_SkipMainnetProbeFalse_RequiresReachableProbe
  • TestConfigured_SkipMainnetProbe_StillRequiresRPC
  • TestConfigured_SkipMainnetProbe_StillRequiresChainID
  • TestValidateChains_MainnetDisabled_RequireMainnetByDefault
  • TestValidateChains_MainnetDisabled_SkipProbeAllowed
  • TestValidateChains_MainnetDisabled_SkipProbe_RequiresRPC
  • TestGetEnvironmentKeys updated for the new env key
• Smoke test: `khedra daemon` with `general.skipMainnetProbe: true` + unreachable mainnet RPC → no wizard.
• Smoke test: `khedra daemon` with `skipMainnetProbe: false` (or omitted) + unreachable mainnet RPC → wizard appears.

[tjayrush]

Hey Chase — thanks for this. Appreciate you digging in.

I can't merge it though. The *bool YAML re-parse creates a hidden three-state boolean — two identical Chain structs with different runtime behavior. It's fragile and surprising.

Simpler approach: add skipMainnetProbe: false to the [general] section. This defaults to false (plain bool, omitted = false), so existing installs are unaffected. Users like you can set it to true. No YAML sniffing, no ambiguity.

Also, new config fields need documentation — book and config.yaml.example.

Happy to discuss further. Hopefully, your AI can do this easily.

[MysticRyuujin]

Thanks for the review @tjayrush — that critique was on point. Pushed a revised version that drops the *bool re-parse entirely and uses a plain skipMainnetProbe: false field in [general], exactly as you suggested.

• Default false, so existing installs are completely unaffected.
• No YAML sniffing, no three-state ambiguity. Configured() and ValidateChains consult cfg.General.SkipMainnetProbe directly.
• mainnet.enabled: false is still rejected by the wizard unless skipMainnetProbe: true is set, and the error message points to the new field.
• Structural checks (mainnet block present, non-empty rpcs, chainId != 0) still apply unconditionally — action_daemon.go reads main.RPCs[0], so we don't want to weaken those.
• Docs added to both config.yaml.example (new note 7) and book/src/user_manual/getting_started.md (note 7 with kurtosis link + env-var override TB_KHEDRA_GENERAL_SKIPMAINNETPROBE).

Test list and details are in the updated PR description.