DMD-1567 Restore use_view on input-mapping-load as load_type=VIEW alias

PR #7570 replaced the boolean use_view field with the load_type enum on
input-mapping-load and made use_view a rejected unexpected field (HTTP 400).
Re-accept use_view additively for backward compatibility, alongside load_type.

- InputMappingConfigTranslator::resolveRequestedLoadType(): single source of
  truth reconciling load_type (concrete wins) and the legacy use_view: true
  alias (-> VIEW); AUTO/omitted/falsy -> null (preflight resolves preferred).
- InputMappingLoadRequest: re-add use_view (Booleanish + OpenAPI property),
  reject a contradictory use_view: true + load_type COPY/CLONE pair (HTTP 400),
  and route isViewRequested() through the resolver so the VIEW guards fire for
  the legacy trigger too. Processor unchanged.
- Docs: apiary.apib (both occurrences), PROJECT_CONTEXT.md.
- Unit + E2E coverage for the alias, conflict, VIEW-incompat and false cases.

Author: vojtabiberle

apiary.apib

@@ -5561,6 +5561,8 @@ Each input item must reference its source via `source` — the full source table
                             + COPY - Copy the data into the workspace.
                             + CLONE - Clone the source table (when supported).
                             + VIEW - Expose the source table as a view (when supported).
+                    + use_view (optional, boolean) - Legacy alias for `load_type: VIEW`, kept for backward compatibility. Cannot be combined with a conflicting `load_type` (`COPY`/`CLONE`).
+                        Default: false
                     + keep_internal_timestamp_column (optional, boolean) - When `false`, the `_timestamp` column is dropped after the load.
                         Default: true
                     + file_type (optional, string) - Accepted for compatibility with the IM payload; no SAPI counterpart, value is ignored.
@@ -5741,6 +5743,8 @@ Same as [Input Mapping Load](#reference/workspaces/input-mapping-load) but scope
                             + COPY - Copy the data into the workspace.
                             + CLONE - Clone the source table (when supported).
                             + VIEW - Expose the source table as a view (when supported).
+                    + use_view (optional, boolean) - Legacy alias for `load_type: VIEW`, kept for backward compatibility. Cannot be combined with a conflicting `load_type` (`COPY`/`CLONE`).
+                        Default: false
                     + keep_internal_timestamp_column (optional, boolean) - When `false`, the `_timestamp` column is dropped after the load.
                         Default: true
                     + file_type (optional, string) - Accepted for compatibility with the IM payload; no SAPI counterpart, value is ignored.