apple-encodings: initial commit (renamed from mac-encodings)

Bidirectional, emulator-grade conversion between classic Mac OS text
encodings and Unicode. Renamed at extraction-to-shared-crate time
(2026-07-19): consumers will be fsinspect, adx, and ad-decoder via git
dependencies on code.movq.us.

README.md

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+# apple-encodings
+
+Bidirectional, emulator-grade conversion between classic Mac OS text encodings
+and Unicode — without linking ICU. The crate owns the canonical Apple tables, so
+it stays small, self-contained, and cross-compiles cleanly.
+
+```rust
+use apple_encodings::{AppleEncoding, MacRomanRevision};
+
+let enc = AppleEncoding::default(); // Mac OS Roman, post-8.5
+assert_eq!(enc.decode(b"Caf\x8e"), "Café");
+assert_eq!(enc.encode("Café").unwrap(), b"Caf\x8e");
+
+// Pick by the Finder Info `fdScript` byte:
+let enc = AppleEncoding::from_script_code(apple_encodings::SCRIPT_ROMAN).unwrap();
+
+// Revision matters for exactly one byte (0xDB):
+let classic = AppleEncoding::MacRoman(MacRomanRevision::Classic);
+assert_eq!(classic.decode(&[0xDB]), "¤"); // pre-8.5 currency sign, not €
+```
+
+## Status
+
+- **Mac OS Roman** — implemented, both pre- and post-8.5 revisions, decode + encode.
+- **Regional single-byte** (Cyrillic, Greek, Turkish, …) and **CJK double-byte**
+  (Japanese, Big5, GB, Korean) — planned, to be codegen'd from the Unicode
+  Consortium `VENDORS/APPLE/*.TXT` tables. The double-byte tables will be
+  feature-gated.
+
+## Scope
+
+Text-encoding conversion only. Unicode normalization concerns (e.g. HFS+'s
+NFD-ish decomposition) are deliberately **out of scope** and left to consumers.
+
+## Consumers
+
+Designed to be shared by `ad-decoder`/`adx` and `fsinspect` via path (and later
+git) dependency.
+
+## License
+
+MIT