fix(wiki): protect inline-code spans from cross-ref injection

_inject_cross_refs temporarily replaces backtick spans with null-byte
placeholders before injecting [[slug]] cross-refs, then restores them.
This prevents concept titles inside `code` from being rewritten.
Add tests for inline-code protection and full-list cross-ref injection.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/wiki/test_compile.py

@@ -212,6 +212,38 @@ def test_inject_cross_refs_replaces_alias() -> None:
     assert "[[circle-packing]]" in result
 
 
+def test_inject_cross_refs_skips_inline_code() -> None:
+    """Concept titles inside backtick inline-code spans are NOT replaced."""
+    concepts = [
+        Concept(
+            slug="circle-packing",
+            title="circle-packing",
+            aliases=[],
+        ),
+        FIXTURE_CONCEPT,
+    ]
+    # The term "circle-packing" appears both bare (should be replaced)
+    # and inside backticks (should NOT be replaced).
+    text = "Use `circle-packing` for this. See also circle-packing theory."
+    result = _inject_cross_refs(text, concepts, current_slug="lobachevsky-function")
+    assert "`circle-packing`" in result  # inline-code preserved
+    assert "[[circle-packing]]" in result  # bare occurrence replaced
+
+
+def test_inject_cross_refs_full_list_even_when_single_concept() -> None:
+    """Cross-ref injection uses the full concept list, not just the compiled concept."""
+    concepts = [
+        Concept(slug="circle-packing", title="Circle Packing", aliases=[]),
+        Concept(slug="discrete-conformal-map", title="Discrete Conformal Map", aliases=[]),
+        FIXTURE_CONCEPT,
+    ]
+    # Compiling lobachevsky-function only; text mentions the other two concepts
+    text = "Discrete Conformal Map is used with Circle Packing."
+    result = _inject_cross_refs(text, concepts, current_slug="lobachevsky-function")
+    assert "[[circle-packing]]" in result
+    assert "[[discrete-conformal-map]]" in result
+
+
 # ---------------------------------------------------------------------------
 # compile_concept (full mock)
 # ---------------------------------------------------------------------------