fix(ci): epsilon guard in cosine similarity (Sonar S1244); fence languages (MD040)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TJc5yvfweHP2AEccKNeaVd

Author: OriNachum

lobes/assess.py

@@ -608,7 +608,9 @@ def _cosine_similarity(a: list[float], b: list[float]) -> float:
     dot = sum(x * y for x, y in zip(a, b))
     norm_a = math.sqrt(sum(x * x for x in a))
     norm_b = math.sqrt(sum(x * x for x in b))
-    if norm_a == 0.0 or norm_b == 0.0:
+    # Norms are non-negative; below this epsilon the vector is degenerate and
+    # the similarity is meaningless (and the division would explode).
+    if norm_a < 1e-12 or norm_b < 1e-12:
         return 0.0
     return dot / (norm_a * norm_b)
 

tests/fixtures/upgrade_compat/README.md

@@ -9,7 +9,7 @@ Source commit: `main` @ `7fa624d1c891c2bc1c5934947d0d9379462605e0`
 
 Vendored verbatim via:
 
-```
+```sh
 git show main:lobes/templates/docker-compose.yml       > single/docker-compose.yml
 git show main:lobes/templates/env.example               > single/env.example
 git show main:lobes/templates/fleet/docker-compose.yml  > fleet/docker-compose.yml

tests/goldens/README.md

@@ -18,7 +18,7 @@ This directory holds the **byte-for-byte** golden files
 
 Regenerate all three with:
 
-```
+```sh
 uv run python tests/goldens/regen.py
 ```