feat(plsql): add extended upstream rules for more complete Oracle support

Adds 28 additional parser rules from upstream:

C External Call Support:
- c_external_parameter, c_property

Analytic Views:
- hierarchies_clause, filter_clause, filter_clauses
- subav_clause, subav_factoring_clause
- add_calc_meas_clause, add_calcs_clause
- aggregate_clause

Utility Rules:
- parallel_instances_clause, overriding_procedure_spec
- assignable_element, connection_qualifier, local_link_name
- by_user_for_statistics_clause, unary_logical_operation
- variable_or_collection, collection_expression
- virtual_column_expression

Partition Values:
- index_partitioning_values_list, range_values_list

SQL*Plus:
- clear_command, start_command, sql_plus_command_no_semicolon

Other:
- expressions_, string_delimiter, system_actions

All 371 tests pass.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: vsai12

plsql/PlSqlParser.g4

@@ -7348,6 +7348,159 @@ filter_condition
     : INCLUDING ROWS where_clause
     ;
 
+// === Extended upstream rules for more complete Oracle support ===
+
+// C external call parameter support (extends c_parameters_clause)
+c_external_parameter
+    : CONTEXT
+    | SELF (TDO | c_property)?
+    | (parameter_name | RETURN) c_property? (BY REFERENCE)? external_datatype=regular_id?
+    ;
+
+c_property
+    : INDICATOR (STRUCT | TDO)?
+    | LENGTH
+    | DURATION
+    | MAXLEN
+    | CHARSETID
+    | CHARSETFORM
+    ;
+
+// Analytic view hierarchies
+hierarchies_clause
+    : HIERARCHIES '(' hier_alias+=object_name (',' hier_alias+=object_name)* ')'
+    ;
+
+// Filter clauses for analytic views
+filter_clause
+    : (MEASURES | hier_alias=object_name) TO condition
+    ;
+
+filter_clauses
+    : FILTER FACT '(' filter_clause (',' filter_clause)* ')'
+    ;
+
+// Subanalytic view support
+subav_clause
+    : USING subav_name=object_name hierarchies_clause? filter_clauses? add_calcs_clause?
+    ;
+
+subav_factoring_clause
+    : subav_name=id_expression ANALYTIC VIEW AS '(' subav_clause ')'
+    ;
+
+// Analytic view calculated measures
+add_calc_meas_clause
+    : meas_name=id_expression AS '(' expression ')'
+    ;
+
+add_calcs_clause
+    : ADD MEASURES '(' add_calc_meas_clause (',' add_calc_meas_clause)* ')'
+    ;
+
+// Aggregate clause for user-defined aggregate functions
+aggregate_clause
+    : AGGREGATE USING implementation_type_name
+    ;
+
+// Parallel instances clause
+parallel_instances_clause
+    : INSTANCES (UNSIGNED_INTEGER | DEFAULT)
+    ;
+
+// Overriding procedure spec for object types
+overriding_procedure_spec
+    : PROCEDURE procedure_name ('(' type_elements_parameter (',' type_elements_parameter)* ')')?
+      (IS | AS) (call_spec | DECLARE? seq_of_declare_specs? body ';')
+    ;
+
+// Assignable element (assignment target)
+assignable_element
+    : general_element
+    | bind_variable
+    ;
+
+// Database link connection qualifier
+connection_qualifier
+    : identifier
+    ;
+
+local_link_name
+    : identifier
+    ;
+
+// Statistics clause
+by_user_for_statistics_clause
+    : BY USER FOR STATISTICS
+    ;
+
+// Unary logical operation
+unary_logical_operation
+    : IS NOT? logical_operation
+    ;
+
+// Variable or collection reference
+variable_or_collection
+    : variable_name
+    | collection_expression
+    ;
+
+// Collection expression
+collection_expression
+    : collation_name '(' expression ')' ('.' general_element_part)*
+    ;
+
+// Virtual column expression definition
+virtual_column_expression
+    : autogenerated_sequence_definition
+    | (GENERATED ALWAYS?)? AS '(' expression ')'
+    ;
+
+// Partition values lists
+index_partitioning_values_list
+    : literal (',' literal)*
+    | TIMESTAMP literal (',' TIMESTAMP literal)*
+    ;
+
+range_values_list
+    : literal (',' literal)*
+    | TIMESTAMP literal (',' TIMESTAMP literal)*
+    ;
+
+// Expression list (with underscore suffix per upstream naming)
+expressions_
+    : expression (',' expression)*
+    ;
+
+// String delimiter helper
+string_delimiter
+    : CHAR_STRING
+    | string_function
+    | string_delimiter BAR BAR string_delimiter
+    | '(' string_delimiter ')'
+    | id_expression
+    ;
+
+// SQL*Plus clear command
+clear_command
+    : CLEAR (COLUMN? regular_id | ALL)
+    ;
+
+// SQL*Plus start command
+start_command
+    : START_CMD id_expression PERIOD (SQL | FILE_EXT)
+    ;
+
+// SQL*Plus command without semicolon
+sql_plus_command_no_semicolon
+    : set_command
+    ;
+
+// System actions for audit
+system_actions
+    : ACTIONS system_privilege (',' system_privilege)*
+    ;
+
 regular_id
     : non_reserved_keywords_pre12c
     | non_reserved_keywords_in_12c