docs(site): add Search mappings guide to MkDocs nav and home page

Publish SEARCH_MAPPINGS_AND_FIELDS.md on sipcapture.github.io/homer.

Author: adubovikov

docs/index.md

@@ -17,6 +17,7 @@ ingest, DuckLake storage, Node (FlightSQL), and Coordinator (REST API).
 |-------|--------|
 | First-time setup | [Config wizard](WIZARD.md) |
 | CLI search | [Search CLI](SEARCH.md) |
+| Dashboard search & mappings | [URL search](SEARCH_URL.md) · [Mappings & fields](SEARCH_MAPPINGS_AND_FIELDS.md) |
 | REST API | [Coordinator](COORDINATOR.md) · [OpenAPI (Swagger)](swagger/index.html) |
 | Storage | [Architecture](STORAGE_ARCHITECTURE.md) · [Policies](STORAGE_POLICIES.md) |
 | Performance | [Ingest tuning](INGEST_PERFORMANCE.md) · [DuckDB tuning](DUCKDB_TUNING.md) |

mkdocs.yml

@@ -74,6 +74,7 @@ nav:
       - Environment variables: ENVIRONMENT_VARIABLES.md
       - Search CLI: SEARCH.md
       - Dashboard URL search: SEARCH_URL.md
+      - Search mappings & fields: SEARCH_MAPPINGS_AND_FIELDS.md
       - Certificates: CERTIFICATES_README.md
   - Architecture:
       - Overview: STORAGE_ARCHITECTURE.md