Use datetime(3) for Job table timestamps

- Add fractional seconds precision support to datetime core type
- Replace timestamp(3) with datetime(3) in Job table definition
- Eliminates native type warnings for job table timestamps

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/datajoint/declare.py

@@ -38,7 +38,7 @@
     "bytes": (r"bytes$", "longblob"),
     # Temporal
     "date": (r"date$", None),
-    "datetime": (r"datetime$", None),
+    "datetime": (r"datetime(\s*\(\d+\))?$", None),  # datetime with optional fractional seconds precision
     # String types (with parameters)
     "char": (r"char\s*\(\d+\)$", None),
     "varchar": (r"varchar\s*\(\d+\)$", None),

src/datajoint/jobs.py

@@ -127,10 +127,10 @@ def _generate_definition(self) -> str:
     ---
     status          : enum('pending', 'reserved', 'success', 'error', 'ignore')
     priority        : uint8
-    created_time=CURRENT_TIMESTAMP(3) : timestamp(3)
-    scheduled_time=CURRENT_TIMESTAMP(3) : timestamp(3)
-    reserved_time=null  : timestamp(3)
-    completed_time=null : timestamp(3)
+    created_time=CURRENT_TIMESTAMP(3) : datetime(3)
+    scheduled_time=CURRENT_TIMESTAMP(3) : datetime(3)
+    reserved_time=null  : datetime(3)
+    completed_time=null : datetime(3)
     duration=null   : float64
     error_message="" : varchar({ERROR_MESSAGE_LENGTH})
     error_stack=null : <blob>