feat(15-02): add Posts admin with mlmarkdown and FormatHTML

YAML-driven Posts screen stores translatable markdown and regenerates
content_html in the plugin. Publish writes without access_publish are
refused; list and form queries stay on the principal without
access_other_posts.

Co-authored-by: Cursor <cursoragent@cursor.com>

controllers/posts/config_filter.yaml

@@ -0,0 +1,14 @@
+scopes:
+    category:
+        label: golem15.journal::lang.posts.filter_category
+        modelClass: Golem15\Journal\Models\Category
+        nameFrom: name
+        scope: FilterCategories
+    published:
+        label: golem15.journal::lang.posts.filter_published
+        type: switch
+        column: published
+    published_date:
+        label: golem15.journal::lang.posts.filter_date
+        type: daterange
+        column: created_at

controllers/posts/config_form.yaml

@@ -0,0 +1,19 @@
+name: golem15.journal::lang.journal.create_post
+form: ~/plugins/golem15/journal/models/post/fields.yaml
+modelClass: Golem15\Journal\Models\Post
+defaultRedirect: golem15/journal/posts
+
+create:
+    redirect: golem15/journal/posts/update/:id
+    redirectClose: golem15/journal/posts
+
+update:
+    redirect: golem15/journal/posts
+    redirectClose: golem15/journal/posts
+
+messages:
+    create: golem15.journal::lang.posts.new_post
+    update: backend::lang.messages.form.update
+    saved: backend::lang.messages.form.saved
+    deleteConfirm: golem15.journal::lang.post.delete_confirm
+    deleted: backend::lang.messages.form.deleted

controllers/posts/config_list.yaml

@@ -0,0 +1,26 @@
+list: ~/plugins/golem15/journal/models/post/columns.yaml
+modelClass: Golem15\Journal\Models\Post
+title: golem15.journal::lang.post.label_plural
+recordUrl: golem15/journal/posts/update/:id
+noRecordsMessage: backend::lang.list.no_records
+recordsPerPage: 25
+showCheckboxes: true
+showSetup: true
+showSorting: true
+filter: config_filter.yaml
+
+defaultSort:
+    column: published_at
+    direction: desc
+
+toolbar:
+    buttons: [create, delete]
+    search:
+        prompt: backend::lang.list.search_prompt
+
+messages:
+    create: golem15.journal::lang.posts.new_post
+    empty: backend::lang.list.no_records
+    deleteConfirm: golem15.journal::lang.post.delete_confirm
+    deleted: backend::lang.messages.list.deleted
+    rowStateDisabled: golem15.journal::lang.journal.chart_drafts