Finch 2.4.0: methods, maps, errors as values; str() of any value; macOS and ARM64 docs; Kate support

- fn Struct.method(...) with self by reference, also on C structs
- map[K]V: insertion-ordered hash maps, literals, m[k] += 1, has/get/remove/keys/values
- -> T! / -> !, return error(...), or <value>, or { err }, try; fallible int/float/read_file/write_file/delete_file
- for i, x in list / for k, v in map
- print and str() share one text formatter
- LSP: method and map completion, method signatures; grammar and snippets for VS Code and Kate
- tests: 74 (methods, errors, maps + 11 failure cases); docs at all three levels, en and pl

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/run/maps.out

@@ -0,0 +1,27 @@
+{"anna": 31, "bob": 26, "cyril": 40} 3
+31 true false -1
+anna is 31
+bob is 26
+cyril is 40
+anna
+bob
+cyril
+true false {"anna": 31, "cyril": 40}
+["anna", "cyril", "dave"] [31, 40, 19]
+{"the": 3, "cat": 1, "and": 2, "dog": 1, "bird": 1}
+{"the": 3, "cat": 1, "and": 2, "dog": 1, "bird": 1}
+{"even": [0, 2, 4, 6, 8], "odd": [1, 3, 5, 7, 9]}
+5 0
+1 2 ["a", "e"]
+2 2 ["bb", "cc"]
+3 1 ["ddd"]
+344 111277621 998001 false
+['h', 'e', 'l', 'o']
+{} 0 3
+{"x": "1"}
+0 zero
+1 one
+2 two
+0 h
+1 e
+2 y