docs(internal): qualify the graph-hit score impossibility claim

The comment said no value of _GRAPH_HIT_SCORE makes fuzzy mode
symmetric, and rested that on _calculate_entity_score having no
ceiling. The absent clamp does not carry the claim: that score is a sum
of bounded parts, so a large enough constant would dominate it. What
actually rules such a constant out is the exact-mode property the
paragraph above asserts - every survivor scores 100 there, and raising
the constant breaks that tie. Name the condition instead of leaving it
implicit.

Author: Patch76

src/ha_mcp/tools/smart_search/_graph.py

@@ -359,14 +359,15 @@ async def fetch_related_buckets(client: Any, entity_id: str) -> GraphResult | No
 # two 0-or-100 signals against a threshold of 100), so a graph hit sorts
 # indistinguishably from a body hit.
 #
-# Fuzzy mode is not symmetric, and no value here makes it so: the 100 cap
-# belongs to the config-body score (``_search_in_dict``), while the NAME score
-# from ``_calculate_entity_score`` accumulates without a ceiling — a name
-# echoing the queried entity's words can pass 100 on its own. So with
-# ``exact_match=False`` a graph-ONLY hit (``_merge_graph_hits`` leaves an
-# already-scored record's score alone) can sort below a match that merely
-# resembles the query, and land on a later page under a small ``limit``. It is
-# still counted in ``total_matches`` unless visibility enforcement scrubs it.
+# Fuzzy mode is not symmetric, and no value here makes it so without breaking
+# the tie above: the 100 cap belongs to the config-body score
+# (``_search_in_dict``), while the NAME score from ``_calculate_entity_score``
+# accumulates without a ceiling — a name echoing the queried entity's words can
+# pass 100 on its own. So with ``exact_match=False`` a graph-ONLY hit
+# (``_merge_graph_hits`` leaves an already-scored record's score alone) can sort
+# below a match that merely resembles the query, and land on a later page under
+# a small ``limit``. It is still counted in ``total_matches`` unless visibility
+# enforcement scrubs it.
 _GRAPH_HIT_SCORE = 100