'wigolo config --set searchBackend=hybrid' reports 'Unknown setting' although --plain lists it (v0.2.1)

[tizerluo]

Bug

On v0.2.1 (ghcr.io/knockoutez/wigolo:0.2.1-full):

$ wigolo config --set searchBackend=hybrid
Unknown setting: searchBackend. Run `wigolo config --plain` to list available keys.

$ wigolo config --plain --json
{"dataDir":"/data","settings":{"browserTypes":null,"maxBrowsers":null,"browserIdleTimeoutMs":null,"searchBackend":null, ... }}

searchBackend appears in the --plain key list and is used as the --set example in docs/configuration.md (wigolo config --set searchBackend=hybrid), but --set rejects it. Same for tlsTier (env WIGOLO_TLS_TIER exists but there is no config.json key for it in --plain output at all).

It looks like the settable-key registry and the display-key registry have drifted apart. As a workaround I configured everything via environment variables (WIGOLO_SEARCH=hybrid, WIGOLO_TLS_TIER=auto), which works fine — but env vars don't survive container recreation unless the orchestrator re-injects them, while config.json in the data volume would.

Environment: docker 0.2.1-full, serve --host 0.0.0.0, Ubuntu 26.04 host.