Today /admin/server-config renders fields by iterating Object.keys(payload) on the YAML value — if a key isn't in instance.yaml, the operator can't see it. They have to know to type it via the JSON-patch textarea (which only renders for empty sections) or SSH and edit YAML.
Adds a known-fields registry (`_KNOWN_FIELDS` in app/api/admin.py) the UI consumes alongside the YAML payload. Renderer shows BOTH:
- existing fields (from YAML) with current value
- known-but-unset fields with dashed-border placeholder + hint, ready to fill in
Renderer (`renderField`, `renderSection`, `collectSection`):
- kind="string"|"secret"|"bool"|"int"|"select"|"object"|"array"|"map" — picks input type
- kind="object" with `fields` — recursive structured form, arbitrary depth (corporate_memory needs 3-4 levels)
- kind="array" with `item_kind` — vertical stack of typed inputs + add/remove buttons
- kind="map" with `key_kind` + `value_kind` — key:value rows + add/remove (used for confidence.base, domain_owners, entity_resolution.entities)
- data-path encoded as JSON segment array so map keys with embedded dots (e.g. 'user_verification.correction') survive collect → patch round-trip
- .cfg-field.is-unset CSS — dashed border, muted label, italic hint
Sections newly exposed (added to _EDITABLE_SECTIONS):
- openmetadata: url, token (secret), cache_ttl_seconds, verify_ssl
- desktop: jwt_issuer, jwt_secret (secret), url_scheme
Known fields populated for existing sections:
- data_source.bigquery: billing_project (the cause of the 403 USER_PROJECT_DENIED footgun when SA can read but not bill the data project), legacy_wrap_views (bigquery_query() wrap for VIEWs — issue #101 default off, ON for view-heavy deployments), max_bytes_per_materialize (cost guardrail)
- data_source.keboola: stack_url, project_id (hints; values already populated)
- ai: base_url (required for openai_compat), structured_output (select)
- corporate_memory: full schema from instance.yaml.example — distribution_mode, approval_mode, review_period_months, notify_on_new_items, sources.{claude_local_md,session_transcripts}, extraction.{model,sensitivity_check,contradiction_check}, confidence.{base,modifiers,decay.{mode,half_life_months,decay_rate_monthly,floor}}, contradiction_detection.{enabled,max_candidates}, entity_resolution.{enabled,entities}, domain_owners, domains
- Known partial: confidence.modifiers is map<string, map<string, float>> — falls through to JSON-textarea with TODO; structured editor for that one shape needs more renderer work
Tests:
- test_admin_server_config_known_fields — registry envelope shape, smoke fixture
- test_admin_server_config_renderer_depth — 4-level nested objects, arrays of strings, maps of floats, dotted-key safety
- test_admin_server_config_corp_memory — full corporate_memory schema, 12 fields incl. nested
- test_admin_server_config — existing tests adjusted for new shape
