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/schemas/triggers/schedule.py

@@ -6,28 +6,7 @@ from pydantic import BaseModel, ConfigDict, Field
 
 
 class ScheduleTriggerConfig(BaseModel):
-    """Config for a cron-driven trigger.
-
-    Validated against ``AutomationTrigger.config`` whenever the
-    persisted ``type`` is ``schedule``. The cron expression is
-    evaluated by Celery Beat's source; the timezone is an IANA name
-    (e.g., ``Africa/Kigali``) and is required so the user's cron is
-    unambiguous across DST boundaries.
-    """
-
     model_config = ConfigDict(extra="forbid")
 
-    cron: str = Field(
-        ...,
-        description=(
-            "Five-field cron expression. Minimum resolution is one "
-            "minute; the form editor warns when intervals tighter "
-            "than 15 minutes are used."
-        ),
-        examples=["0 9 * * 1-5"],
-    )
-    timezone: str = Field(
-        ...,
-        description="IANA timezone name (e.g., 'Africa/Kigali', 'UTC').",
-        examples=["Africa/Kigali"],
-    )
+    cron: str = Field(..., description="Five-field cron expression.", examples=["0 9 * * 1-5"])
+    timezone: str = Field(..., description="IANA timezone.", examples=["Africa/Kigali"])