refactor(models): split models.py into topical submodules

decnet/web/db/models.py was approaching 1000 lines across User/Log/
Attacker/Swarm/Topology/Workers/Updater/Health domains. Split into a
package with one module per domain; __init__.py re-exports every symbol
so all 52 call sites keep importing from decnet.web.db.models
unchanged.

decnet/web/db/models/deploy.py

@@ -0,0 +1,19 @@
+"""Fleet deploy + mutate-interval request DTOs."""
+from typing import Optional
+
+from pydantic import BaseModel, ConfigDict, Field as PydanticField
+
+from decnet.models import IniContent
+
+
+class MutateIntervalRequest(BaseModel):
+    # Human-readable duration: <number><unit> where unit is m(inutes), d(ays), M(onths), y/Y(ears).
+    # Minimum granularity is 1 minute. Seconds are not accepted.
+    mutate_interval: Optional[str] = PydanticField(None, pattern=r"^[1-9]\d*[mdMyY]$")
+
+
+class DeployIniRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+    # This field now enforces strict INI structure during Pydantic initialization.
+    # The OpenAPI schema correctly shows it as a required string.
+    ini_content: IniContent = PydanticField(..., description="A valid INI formatted string")