* fix(config): surface unknown/typo'd config fields instead of silently dropping them
json.Unmarshal ignores unknown JSON keys by default, so typos such as
"maxTurn" or "sandbox.network" were silently discarded: the user
believed a setting (e.g. a sandbox hardening option) was active while
Zero used its default. Worse, "zero doctor" reported
"config files parsed and validated successfully" even when fields were dropped.
Add a reflection-based unknown-field scanner
(internal/config/unknownfields.go) that walks the FileConfig JSON schema
and recurses into nested objects, arrays, and maps, reporting each
unknown key with its full JSON path and a near-match suggestion
("did you mean 'maxTurns'?"). The two legacy top-level aliases
(mcpServers, mcp_servers) are allowlisted so they are not flagged,
and detection only inspects json tags, so a config written by a newer
Zero with new fields still loads and merges normally — validate/doctor
just surface the unknown keys as issues rather than rejecting the file.
Wire the scanner into ValidateBytes/ValidateFile, which zero doctor
already uses, so doctor now reports the unknown fields instead of
"validation passed".
Add tests for unknown top-level keys, unknown nested keys, unknown
keys inside a provider entry, and that the legacy aliases are not
flagged.
Fixes#644
* fix(config): address review comments on unknown-field scanner
- Treat JSON keys case-insensitively (matching encoding/json), so a
valid case variant such as "MaxTurns" is not falsely flagged as
unknown. Canonical (correct-case) names are kept only for the
"did you mean" hint.
- Allowlist ProviderProfile's legacy snake_case keys (providerKind,
catalog_id, base_url, api_key, ...) that ProviderProfile.UnmarshalJSON
accepts but which are not fields on the Go type, so existing
configs using them are not false-positive'd in zero doctor.
- Make the near-match suggestion deterministic: sort candidates before
picking so an edit-distance tie always resolves to the same lexical
winner (map-range order was nondeterministic and could flake).
- Make the unknown-field test assertions order-independent (search by
FieldPath instead of assuming issues[0]).
Add regression coverage for legacy provider keys and valid case
variants not being flagged.
