fix: make entity_registry.research() local-only by default

research() previously called _wikipedia_lookup() unconditionally,
sending entity names to en.wikipedia.org on every uncached lookup.
This violates the project's local-first and privacy-by-architecture
principles documented in CLAUDE.md.

Changes:
- research() now returns "unknown" for uncached words by default
- New allow_network=True parameter required for Wikipedia lookups
- Wikipedia 404 now returns "unknown" instead of asserting "person"
  with 0.70 confidence, preventing entity registry poisoning
- Added privacy warning docstring to _wikipedia_lookup()
- Added tests for local-only default, opt-in network, 404 handling,
  and cache-not-persisted-on-local-only behaviour

Refs: #809

Author: Kesshite

mempalace/entity_registry.py

@@ -178,6 +178,12 @@ def _wikipedia_lookup(word: str) -> dict:
     Look up a word via Wikipedia REST API.
     Returns inferred type (person/place/concept/unknown) + confidence + summary.
     Free, no API key, handles disambiguation pages.
+
+    **Privacy warning:** This function makes an outbound HTTPS request to
+    en.wikipedia.org, sending the queried word over the network.  It should
+    only be called when the caller has explicitly opted in via
+    ``allow_network=True`` in :meth:`EntityRegistry.research`.  The default
+    behaviour of ``research()`` is local-only (no network calls).
     """
     try:
         url = f"https://en.wikipedia.org/api/rest_v1/page/summary/{urllib.parse.quote(word)}"
@@ -244,13 +250,14 @@ def _wikipedia_lookup(word: str) -> dict:
 
     except urllib.error.HTTPError as e:
         if e.code == 404:
-            # Not in Wikipedia — strong signal it's a proper noun (unusual name, nickname)
+            # Not in Wikipedia — this tells us nothing definitive about
+            # the word.  Return "unknown" so the caller can decide.
             return {
-                "inferred_type": "person",
-                "confidence": 0.70,
+                "inferred_type": "unknown",
+                "confidence": 0.3,
                 "wiki_summary": None,
                 "wiki_title": None,
-                "note": "not found in Wikipedia — likely a proper noun or unusual name",
+                "note": "not found in Wikipedia",
             }
         return {"inferred_type": "unknown", "confidence": 0.0, "wiki_summary": None}
     except (urllib.error.URLError, OSError, json.JSONDecodeError, KeyError):
@@ -502,17 +509,36 @@ def _disambiguate(self, word: str, context: str, person_info: dict) -> Optional[
 
     # ── Research unknown words ───────────────────────────────────────────────
 
-    def research(self, word: str, auto_confirm: bool = False) -> dict:
+    def research(self, word: str, auto_confirm: bool = False, allow_network: bool = False) -> dict:
         """
-        Research an unknown word via Wikipedia.
-        Caches result. If auto_confirm=False, marks as unconfirmed (needs user review).
-        Returns the lookup result.
+        Research an unknown word.
+
+        By default this is **local-only**: it checks the wiki cache and
+        returns ``"unknown"`` for uncached words.  Pass
+        ``allow_network=True`` to explicitly opt in to an outbound
+        Wikipedia lookup.  This design honours the project's
+        *local-first, zero API* and *privacy by architecture* principles
+        — no data leaves the machine unless the caller requests it.
+
+        Caches result.  If *auto_confirm* is ``False``, marks the entry
+        as unconfirmed (needs user review).
         """
         # Already cached?
         cache = self._data.setdefault("wiki_cache", {})
         if word in cache:
             return cache[word]
 
+        if not allow_network:
+            return {
+                "inferred_type": "unknown",
+                "confidence": 0.0,
+                "wiki_summary": None,
+                "wiki_title": None,
+                "word": word,
+                "confirmed": False,
+                "note": "network lookup disabled — pass allow_network=True to query Wikipedia",
+            }
+
         result = _wikipedia_lookup(word)
         result["word"] = word
         result["confirmed"] = auto_confirm

tests/test_entity_registry.py

@@ -213,10 +213,45 @@ def test_lookup_ambiguous_word_as_concept(tmp_path):
     assert result["type"] == "concept"
 
 
-# ── research (Wikipedia) — mocked ──────────────────────────────────────
+# ── research — local-only by default ───────────────────────────────────
+
+
+def test_research_local_only_by_default(tmp_path):
+    """research() must NOT call Wikipedia unless allow_network=True."""
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.seed(mode="personal", people=[], projects=[])
+
+    with patch(
+        "mempalace.entity_registry._wikipedia_lookup",
+        side_effect=AssertionError("network call should not happen"),
+    ):
+        result = registry.research("Saoirse")
+
+    assert result["inferred_type"] == "unknown"
+    assert result["confidence"] == 0.0
+    assert result["word"] == "Saoirse"
+    assert "network lookup disabled" in result.get("note", "")
+
+
+def test_research_with_allow_network(tmp_path):
+    """research(allow_network=True) calls Wikipedia and caches result."""
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.seed(mode="personal", people=[], projects=[])
+
+    mock_result = {
+        "inferred_type": "person",
+        "confidence": 0.80,
+        "wiki_summary": "Saoirse is an Irish given name.",
+        "wiki_title": "Saoirse",
+    }
+
+    with patch("mempalace.entity_registry._wikipedia_lookup", return_value=mock_result):
+        result = registry.research("Saoirse", auto_confirm=True, allow_network=True)
+    assert result["inferred_type"] == "person"
 
 
 def test_research_caches_result(tmp_path):
+    """Once cached via allow_network, subsequent calls use cache without network."""
     registry = EntityRegistry.load(config_dir=tmp_path)
     registry.seed(mode="personal", people=[], projects=[])
 
@@ -228,7 +263,7 @@ def test_research_caches_result(tmp_path):
     }
 
     with patch("mempalace.entity_registry._wikipedia_lookup", return_value=mock_result):
-        result = registry.research("Saoirse", auto_confirm=True)
+        result = registry.research("Saoirse", auto_confirm=True, allow_network=True)
     assert result["inferred_type"] == "person"
 
     # Second call should use cache, not call Wikipedia again
@@ -240,6 +275,15 @@ def test_research_caches_result(tmp_path):
     assert cached["inferred_type"] == "person"
 
 
+def test_research_local_only_not_cached(tmp_path):
+    """Local-only result for uncached word should NOT be persisted to cache."""
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.seed(mode="personal", people=[], projects=[])
+
+    registry.research("Xander")  # local-only, no network
+    assert "Xander" not in registry._data.get("wiki_cache", {})
+
+
 def test_confirm_research_adds_to_people(tmp_path):
     registry = EntityRegistry.load(config_dir=tmp_path)
     registry.seed(mode="personal", people=[], projects=[])
@@ -251,13 +295,32 @@ def test_confirm_research_adds_to_people(tmp_path):
         "wiki_title": "Saoirse",
     }
     with patch("mempalace.entity_registry._wikipedia_lookup", return_value=mock_result):
-        registry.research("Saoirse", auto_confirm=False)
+        registry.research("Saoirse", auto_confirm=False, allow_network=True)
 
     registry.confirm_research("Saoirse", entity_type="person", relationship="friend")
     assert "Saoirse" in registry.people
     assert registry.people["Saoirse"]["source"] == "wiki"
 
 
+def test_wikipedia_404_returns_unknown(tmp_path):
+    """A 404 from Wikipedia should return 'unknown', not assert 'person'."""
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.seed(mode="personal", people=[], projects=[])
+
+    mock_result = {
+        "inferred_type": "unknown",
+        "confidence": 0.3,
+        "wiki_summary": None,
+        "wiki_title": None,
+        "note": "not found in Wikipedia",
+    }
+    with patch("mempalace.entity_registry._wikipedia_lookup", return_value=mock_result):
+        result = registry.research("Zzxqy", auto_confirm=False, allow_network=True)
+
+    assert result["inferred_type"] == "unknown"
+    assert result["confidence"] < 0.5
+
+
 # ── extract_people_from_query ───────────────────────────────────────────