Document hash pseudonym strategy (0.9.0)

README.md

@@ -105,9 +105,13 @@ r.deidentify(text, spans)                # .text + .mapping
 Beyond redaction, both redactors support:
 
 - **`deidentify()`** — replaces each entity with a consistent pseudonym
-  (`Person_1`) and returns the entity→pseudonym mapping so an authorized
-  key-holder can re-link later. In images, pseudonyms are rendered in
-  place; faces/signatures become neutral placeholders.
+  and returns the entity→pseudonym mapping so an authorized key-holder can
+  re-link later. Two strategies: sequential (`Person_1`, default) or
+  `strategy="hash"` for globally deterministic tokens (`Person_a3f9c1`,
+  md5 of the value — same value, same token across all documents;
+  salt with `secret=` to resist dictionary reversal). In images,
+  pseudonyms are rendered in place; faces/signatures become neutral
+  placeholders.
 - **`anonymize()`** — one-way: ages become 10-year buckets, dates keep only
   the year, fine geography collapses to `[LOCATION]`, names/IDs become
   unnumbered tokens, and faces/signatures are filled solid black. No