Task LAV-2921: Snowflake-managed Iceberg clone: CREATE ICEBERG TABLE … CLONE and Iceberg tables inside SCHEMA / DATABASE clones (#3299)

* task LAV-2921: WIP — commit stranded agent work

* Task LAV-2921: clone managed & dynamic Iceberg tables inside SCHEMA/DATABASE clone

Route managed Iceberg tables through the Iceberg-aware per-table clone (auto
mode) and dynamic Iceberg tables through the DT clone loop so a container clone
reproduces them as Iceberg / dynamic Iceberg tables (is_iceberg=Y, is_dynamic=Y,
SUSPENDED, is_clone). Add real-Snowflake-captured compat tests for schema and
database clones over managed and dynamic Iceberg sources.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Task LAV-2921: direct Iceberg clone time-travel anchors + docs

Add AT/BEFORE (TIMESTAMP/OFFSET/STATEMENT) coverage for CREATE ICEBERG TABLE …
CLONE (reusing the table-level time-travel clone path, incl. the out-of-window
and statement-not-found errors), and update docs/architecture/iceberg-tables.md
CLONE rows to the implemented behaviour.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Task LAV-2921: skip externally-managed Iceberg tables in container clone

An externally-managed / catalog-linked Iceberg table (iceberg_tables row with
catalog_table_name or metadata_file_path) is not caught by is_external_table, so
the container plain-clone loop would drop it to a plain heap — which real
Snowflake never produces for an Iceberg source. Skip it like external tables.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Wojciech Padło <wojciech.padlo@localstack.cloud>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

src/dialect/snowflake.rs

@@ -784,6 +784,14 @@ impl SnowflakeDialect {
                 _ => {}
             }
 
+            // `CREATE [OR REPLACE] TRANSIENT ICEBERG TABLE` — the TRANSIENT
+            // modifier may precede ICEBERG (mirrors TRANSIENT DYNAMIC above);
+            // the modifier group only matches one keyword, so pick up ICEBERG
+            // here after a leading TRANSIENT.
+            if transient && !iceberg && parser.parse_keyword(Keyword::ICEBERG) {
+                iceberg = true;
+            }
+
             if scoped && !temporary {
                 return Some(parser.expected("TEMPORARY after SCOPED", parser.peek_token()));
             }
@@ -3087,13 +3095,15 @@ pub fn parse_create_table(
 
     // Snowflake-managed Iceberg tables require BASE_LOCATION. Tables bound to
     // an external catalog integration (an explicit non-SNOWFLAKE CATALOG, or
-    // CATALOG_TABLE_NAME for externally-managed reads) do not.
+    // CATALOG_TABLE_NAME for externally-managed reads) do not, and neither does
+    // a clone (CREATE ICEBERG TABLE … CLONE inherits the source's location).
     let external_catalog = builder
         .catalog
         .as_deref()
         .is_some_and(|c| !c.eq_ignore_ascii_case("SNOWFLAKE"));
     if iceberg
         && !dynamic
+        && builder.clone.is_none()
         && builder.base_location.is_none()
         && builder.catalog_table_name.is_none()
         && builder.metadata_file_path.is_none()