feat: multi-turn conversation support (0.4.0)

anonymizeTurn(text, session) threads a serializable AnonymizerSession
({mapping, legend, history}) so one entity keeps one id across a whole chat
(applyKnown reuse + usedIds + de-collision merge). Adds conversation()
in-memory wrapper and an optional LlmProvider.anonymizeInConversation(text, ctx)
for rich cross-turn context; providers without it fall back to the batch path.

openAICompatibleProvider gains includeMappingInContext (default false — only
send real values to a trusted anonymizer endpoint) + historyMaxTurns (default
10). Verified live vs Gemma 4: Nora stays PER_1 across 4 turns (name/email/AVS/
IBAN), Yanis = PER_2; 41 tests, 98% coverage.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mobiletic/anonymizer",
-  "version": "0.3.1",
+  "version": "0.4.0",
   "description": "Framework-agnostic PII anonymization & pseudonymization: pluggable LLM detection for free-form PII (names, addresses) with a deterministic regex fallback, deterministic coreference, and streaming-safe de-anonymization.",
   "license": "MIT",
   "author": "Mobiletic",