feat: stdlib daily APIs, macro tt/type paste, riscv64 cross smoke

Sessions 83–87: grow Array/Map/String/Test ergonomics; delimiter-balanced
and juxta :tt macros plus $t:type fragments; expression-level $(…),* in
templates; selfhost slice lits; riscv64/aarch64 cross smoke helper and
freestanding docs. Null-safe CBE type names and String_StartsWith.

Makefile

@@ -5,10 +5,10 @@ BUILD_DIR := build
 # Project-local nimcache so CI can cache compiles (default is ~/.cache/nim).
 NIMFLAGS ?= --nimcache:nimcache
 
-EXAMPLES := hello fibonacci factorial structs enums methods algebraic_enums generics generics_struct generic_infer generic_infer2 extend_generic pattern_matching strings strings2 map result_option try_operator ownership ownership_checked ownership_release drop_early_return lifetime_elision ctfe ctfe_crc async concurrency os_time process json iter trait_bounds channel sync jwt stdlib_ergonomics tuples func_ptr map_remove array_iter_extra string_extra multi_closure iter_hof closure_control match_let string_interp iter_generic generic_infer_hof struct_tuple_pat match_block nested_patterns match_guards pattern_shadow move_field move_field_partial move_field_remaining move_field_nested move_field_ptr move_cross_fn c_precedence macro_twice macro_repeat macro_nested macro_hygiene macro_unhygienic macro_stmt_pat macro_tt
+EXAMPLES := hello fibonacci factorial structs enums methods algebraic_enums generics generics_struct generic_infer generic_infer2 extend_generic pattern_matching strings strings2 map result_option try_operator ownership ownership_checked ownership_release drop_early_return lifetime_elision ctfe ctfe_crc async concurrency os_time process json iter trait_bounds channel sync jwt stdlib_ergonomics tuples func_ptr map_remove array_iter_extra string_extra multi_closure iter_hof closure_control match_let string_interp iter_generic generic_infer_hof struct_tuple_pat match_block nested_patterns match_guards pattern_shadow move_field move_field_partial move_field_remaining move_field_nested move_field_ptr move_cross_fn c_precedence macro_twice macro_repeat macro_nested macro_hygiene macro_unhygienic macro_stmt_pat macro_tt macro_tt_raw macro_type collections_extra
 
 # Platform smoke (macOS CI): full EXAMPLES still runs on Linux.
-EXAMPLES_SMOKE := hello ownership ownership_release strings map move_field move_field_partial move_field_remaining move_field_nested move_field_ptr move_cross_fn c_precedence macro_twice macro_repeat macro_nested macro_hygiene macro_unhygienic macro_stmt_pat macro_tt ctfe_crc
+EXAMPLES_SMOKE := hello ownership ownership_release strings map move_field move_field_partial move_field_remaining move_field_nested move_field_ptr move_cross_fn c_precedence macro_twice macro_repeat macro_nested macro_hygiene macro_unhygienic macro_stmt_pat macro_tt macro_tt_raw ctfe_crc
 
 .PHONY: all build dev debug test clean clean-all test-examples test-examples-smoke selfhost test-golden test-errors test-stdlib selfhost-loop lsp fmt-check docs bench test-apps test-dwarf test-selfhost-smoke test-unit test-linux-targets ensure-buxc
 
@@ -265,10 +265,10 @@ test-dwarf: ensure-buxc
 	@chmod +x tools/smoke_dwarf.sh
 	@tools/smoke_dwarf.sh
 
-# Session 75 — Linux / cloud / embedded: minimal runtime, static, aarch64 cross, CTFE CRC
+# Session 75/85 — Linux / cloud / embedded: minimal, static, aarch64+riscv64 cross, CTFE CRC
 .PHONY: test-linux-targets
 test-linux-targets: ensure-buxc
-	@echo "=== Linux targets smoke (minimal / static / cross) ==="
+	@echo "=== Linux targets smoke (minimal / static / aarch64+riscv64 cross) ==="
 	@chmod +x tools/smoke_linux_targets.sh
 	@tools/smoke_linux_targets.sh