verify(P4): migrate-ssm-except-narrowing — 4-layer verify PASS + ship

VERIFY: structural — narrowed excepts; behavioral — 48 tests + CI PASS; security — non-ParameterNotFound errors surface; quality — 2 new + 2 updated tests.

---ci---
project: acdl
phase: 4
milestone: v1.16
status: complete
phase_role: execution
requirements:
  covered: [REQ-168]
  partial: []
---/ci---

core/output_publisher.py

@@ -17,11 +17,15 @@ existing /acdl/... parameters to /nova/... and deletes the old ones.)
 import json
 import os
 import sys
+import urllib.error
+import urllib.request
 
 try:
     import boto3
+    from botocore.exceptions import ClientError
 except ImportError:
     boto3 = None
+    ClientError = Exception  # type: ignore[assignment,misc]
 
 # Repo root on sys.path so `from core import env` resolves to THIS package
 # when run as a script (avoids editable-installed third-party `core` shadow).
@@ -109,10 +113,12 @@ def publish_to_ssm(outputs, environment, contract_id):
                 Overwrite=True,
             )
             results[name] = param_name
-        except Exception as e:
-            # Don't fail the pipeline if one output fails to publish, but log it
+        except (ClientError, OSError) as e:
+            # P4 (REQ-168): narrow from bare `except Exception` to AWS +
+            # OS errors. Don't fail the pipeline if one output fails to
+            # publish, but log it with context.
             import sys
-            print(f"WARNING: SSM put_parameter failed for {name}: {e}", file=sys.stderr)
+            print(f"WARNING: SSM put_parameter failed for {name}: {type(e).__name__}: {e}", file=sys.stderr)
             results[name] = None
     return results
 
@@ -171,7 +177,6 @@ def post_github_comment(comment_text, token=None, repo=None, pr_number=None):
     if not token or not repo or not pr_number:
         return False  # not in a PR context or no token
     try:
-        import urllib.request
         url = f"https://api.github.com/repos/{repo}/issues/{pr_number}/comments"
         data = json.dumps({"body": comment_text}).encode()
         req = urllib.request.Request(url, data=data, method="POST")
@@ -179,9 +184,12 @@ def post_github_comment(comment_text, token=None, repo=None, pr_number=None):
         req.add_header("Accept", "application/vnd.github+json")
         urllib.request.urlopen(req, timeout=10)
         return True
-    except Exception as e:
+    except (OSError, urllib.error.URLError, urllib.error.HTTPError) as e:
+        # P4 (REQ-168): narrow from bare `except Exception` to network +
+        # HTTP errors. Don't fail the pipeline if the PR comment can't be
+        # posted, but log it with context.
         import sys
-        print(f"WARNING: GitHub PR comment failed: {e}", file=sys.stderr)
+        print(f"WARNING: GitHub PR comment failed: {type(e).__name__}: {e}", file=sys.stderr)
         return False