feat: Notifiers CRUD (#337)

* introduce scaffold for new models

* wip: shoutrrr wrapper (may remove)

* update schema files

* gen: ent code

* gen: migrations

* go mod tidy

* add group_id to notifier

* db migration

* new mapper helpers

* notifier repo

* introduce experimental adapter pattern for hdlrs

* refactor adapters to fit more common use cases

* new routes for notifiers

* update errors to fix validation panic

* go tidy

* reverse checkbox label display

* wip: notifiers UI

* use badges instead of text

* improve documentation

* add scaffold schema reference

* remove notifier service

* refactor schema folder

* support group edges via scaffold

* delete test file

* include link to API docs

* audit and update documentation + improve format

* refactor schema edges

* refactor

* add custom validator

* set validate + order fields by name

* fix failing tests

.scaffold/model/scaffold.yaml

@@ -0,0 +1,33 @@
+---
+# yaml-language-server: $schema=https://hay-kot.github.io/scaffold/schema.json
+messages:
+  pre: |
+    # Ent Model Generation
+
+    With Boilerplate!
+  post: |
+    Complete!
+
+questions:
+  - name: "model"
+    prompt:
+      message: "What is the name of the model? (PascalCase)"
+    required: true
+
+  - name: "by_group"
+    prompt:
+      confirm: "Include a Group Edge? (group_id -> id)"
+    required: true
+
+rewrites:
+  - from: 'templates/model.go'
+    to: 'backend/internal/data/ent/schema/{{ lower .Scaffold.model }}.go'
+
+inject:
+  - name: "Insert Groups Edge"
+    path: 'backend/internal/data/ent/schema/group.go'
+    at: // $scaffold_edge
+    template: |
+      {{- if .Scaffold.by_group -}}
+      owned("{{ lower .Scaffold.model }}s", {{ .Scaffold.model }}.Type),
+      {{- end -}}