citations: normalize word-glued [n] markers

The model frequently writes citations glued to the preceding word
(docs[17]); the (?<!\w) lookbehind (added to dodge arr[1] array indexing)
silently skipped these, leaving raw [n] that fails to render and reads
like array access. Drop the lookbehind so glued citations resolve; genuine
code/array syntax stays protected by the existing code-region carve-out and
unresolved ordinals still drop harmlessly.

surfsense_backend/app/agents/chat/multi_agent_chat/shared/citations/normalizer.py

@@ -19,10 +19,14 @@ from .registry import CitationRegistry
 # code-region pattern so ordinals inside examples are never rewritten.
 _CODE_REGION = re.compile(r"```[\s\S]*?```|`[^`\n]+`")
 
-# A single ordinal in a bracket: `[1]`, `[12]`. Not preceded by a word char, so
-# index expressions like `arr[1]` are left alone, while adjacent citations like
-# `[1][2]` (second bracket follows `]`) are both rewritten.
-_ORDINAL = re.compile(r"(?<!\w)\[\s*(\d+)\s*\]")
+# A single ordinal in a bracket: `[1]`, `[12]`. We deliberately match even when
+# glued to the preceding word (`docs[17]`) because the model very frequently
+# writes citations that way — requiring a non-word char before `[` (to dodge
+# `arr[1]`) silently dropped those citations, leaving raw `[n]` that both fails to
+# render and reads like array indexing. Genuine code/array syntax is instead
+# protected by the code-region carve-out below; an unresolved ordinal drops
+# harmlessly. Adjacent citations `[1][2]` are each rewritten.
+_ORDINAL = re.compile(r"\[\s*(\d+)\s*\]")
 
 
 def normalize_citations(text: str, registry: CitationRegistry) -> str:

surfsense_backend/tests/unit/agents/multi_agent_chat/shared/citations/test_normalizer.py

@@ -65,11 +65,30 @@ def test_web_result_rewrites_to_url() -> None:
     )
 
 
-def test_index_expression_is_left_alone() -> None:
+def test_word_glued_citation_is_rewritten() -> None:
+    # The model frequently writes citations glued to the preceding word
+    # (``docs[1]``); these must still resolve to a marker, not leak as raw text.
     registry = _registry_with_chunks(42)
 
-    assert normalize_citations("Read arr[1] carefully.", registry) == (
-        "Read arr[1] carefully."
+    assert normalize_citations("verifying against docs[1].", registry) == (
+        "verifying against docs[citation:42]."
+    )
+
+
+def test_word_glued_unknown_ordinal_drops() -> None:
+    # A glued ordinal that doesn't resolve drops harmlessly (no broken marker,
+    # no raw ``[n]`` leak) rather than being preserved as array-index syntax.
+    registry = _registry_with_chunks(42)
+
+    assert normalize_citations("see notes[9] later", registry) == "see notes later"
+
+
+def test_array_index_inside_code_is_left_alone() -> None:
+    # Genuine array/index syntax is protected by the code-region carve-out.
+    registry = _registry_with_chunks(42)
+
+    assert normalize_citations("Read `arr[1]` carefully.", registry) == (
+        "Read `arr[1]` carefully."
     )