chore(automation): trim docstrings to intent only

Cut the docstrings and Field(description=...) text across the entire
automations/ tree down to single-line intent statements, matching the
multi_agent_chat conciseness style:

- Module docstrings: one line stating what the file is.
- Class docstrings: deleted when the class name + module docstring
  already cover intent; kept only where they add a constraint or
  rationale not visible in the signature.
- Pydantic Field descriptions: short noun phrases / clauses, not
  full sentences. Reasoning that belonged in the design plan moved
  out of the code.
- Enum values: per-value docstrings replaced with terse inline
  comments where the meaning isn't obvious from the name.

Behaviour is unchanged. The same 33 files, same public surface, same
imports — verified by re-running the 10-point registry smoke test and
the 8-point schema round-trip / constraint suite from commits 9 and
10.

LOC: 1180 → 691 (-42%).

surfsense_backend/app/automations/registries/triggers/store.py

@@ -1,4 +1,4 @@
-"""Trigger registry: in-memory dict + ``register_trigger`` API."""
+"""In-memory trigger registry. Populated once at process startup."""
 
 from __future__ import annotations
 
@@ -8,26 +8,16 @@ _REGISTRY: dict[str, TriggerDefinition] = {}
 
 
 def register_trigger(trigger: TriggerDefinition) -> None:
-    """Add a trigger to the in-memory registry.
-
-    Raises ``ValueError`` on duplicate ``type`` — registration runs
-    once per process, so a duplicate is always a bug.
-    """
-
+    """Register a trigger. Raises on duplicate type."""
     if trigger.type in _REGISTRY:
-        raise ValueError(
-            f"Trigger already registered: {trigger.type!r}"
-        )
+        raise ValueError(f"Trigger already registered: {trigger.type!r}")
     _REGISTRY[trigger.type] = trigger
 
 
 def get_trigger(trigger_type: str) -> TriggerDefinition | None:
-    """Look up one trigger by type. Returns ``None`` on miss."""
-
     return _REGISTRY.get(trigger_type)
 
 
 def all_triggers() -> dict[str, TriggerDefinition]:
-    """Snapshot of the registry as a defensive copy."""
-
+    """Defensive snapshot of the registry."""
     return dict(_REGISTRY)