Address PR review comments for nexus_helpers

- Move `import re` to module-level imports instead of inside functions
- Update docstring to mention that generated dict includes topic info
- Include 'topic' key in generated f144_log_streams dictionary entries
- Update test assertions to match new output format with topic

Addresses review comments from PR #589.

Original prompt: Please use a new worktree to address comments in a #589. Commit and push, then cleanup worktree.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: SimonHeybrock

src/ess/livedata/nexus_helpers.py

@@ -7,6 +7,7 @@
 
 from __future__ import annotations
 
+import re
 from dataclasses import dataclass
 from pathlib import Path
 
@@ -134,8 +135,6 @@ def suggest_internal_name(info: StreamInfo) -> str:
             if i > 0:
                 name = parts[i - 1]
                 # Remove common suffixes like '_r0', '_01' etc.
-                import re
-
                 name = re.sub(r'_[rt]\d+$', '', name)
                 return name
     # Fallback: use last non-value component
@@ -159,8 +158,6 @@ def filter_f144_streams(
     exclude_patterns:
         List of regex patterns to exclude from results (matched against group_path).
     """
-    import re
-
     exclude_patterns = exclude_patterns or []
     exclude_regexes = [re.compile(p) for p in exclude_patterns]
 
@@ -184,7 +181,7 @@ def generate_f144_log_streams_code(
 ) -> str:
     """Generate Python code for f144_log_streams dictionary.
 
-    The generated dictionary maps internal names to source and units info,
+    The generated dictionary maps internal names to source, units, and topic info,
     which can be used to derive both f144_attribute_registry and StreamLUT.
 
     Parameters
@@ -215,9 +212,11 @@ def generate_f144_log_streams_code(
     for name in sorted(by_name.keys()):
         info = by_name[name]
         units = info.units or 'dimensionless'
-        lines.append(
-            f"    '{name}': {{'source': '{info.source}', 'units': '{units}'}},"
+        entry = (
+            f"    '{name}': {{'source': '{info.source}', 'units': '{units}', "
+            f"'topic': '{topic}'}}"
         )
+        lines.append(f"{entry},")
 
     lines.append("}")
     return '\n'.join(lines)

tests/nexus_helpers_test.py

@@ -510,7 +510,10 @@ def test_generates_valid_python_dict(self) -> None:
         ]
         code = generate_f144_log_streams_code(infos, topic='motion')
         assert "f144_log_streams: dict[str, dict[str, str]] = {" in code
-        assert "'motor': {'source': 'MOTOR:PV:RBV', 'units': 'degrees'}" in code
+        assert (
+            "'motor': {'source': 'MOTOR:PV:RBV', 'units': 'degrees', 'topic': 'motion'}"
+            in code
+        )
 
     def test_uses_dimensionless_for_empty_units(self) -> None:
         infos = [
@@ -525,7 +528,7 @@ def test_uses_dimensionless_for_empty_units(self) -> None:
             ),
         ]
         code = generate_f144_log_streams_code(infos, topic='motion')
-        assert "'units': 'dimensionless'" in code
+        assert "'units': 'dimensionless', 'topic': 'motion'" in code
 
     def test_prefers_value_over_idle_flag(self) -> None:
         infos = [