chore: brought RuDS up to bDS2 alignment, as that is the new baseline we want to hit

specs/post.allium

@@ -5,14 +5,20 @@
 
 use "./project.allium" as project
 
+enum PostStatus {
+    draft
+    published
+    archived
+}
+
 value Slug {
     value: String
 
     -- Generated by: transliterate unicode to ASCII, lowercase,
     -- replace [^a-z0-9]+ with hyphens, strip leading/trailing hyphens
     -- Transliteration scope: only German (ä/ö/ü/ß/ÄÖÜ) and English letters used.
-    -- Verify deunicode handles this set correctly against transliteration npm.
-    -- Uniqueness: tries base, then {slug}-2 .. {slug}-999, then {slug}-{timestamp}
+    -- Verify transliteration matches the established bDS behaviour for this set.
+    -- Uniqueness: tries base, then {slug}-2, {slug}-3, … (unbounded numeric suffix)
 }
 
 value PostFilePath {
@@ -40,13 +46,51 @@ value Frontmatter {
     --   doNotTranslate (only when true), templateSlug, publishedAt
 }
 
+surface PostControlSurface {
+    facing _: PostOperator
+
+    provides:
+        CreatePostRequested(project, title, content, tags, categories, author, language, template_slug)
+        UpdatePostRequested(post, changes)
+        PublishPostRequested(post)
+        DeletePostRequested(post)
+        ArchivePostRequested(post)
+        DiscardPostChangesRequested(post)
+        SyncPostFromFileRequested(post)
+        ImportOrphanPostFileRequested(project, relative_path)
+}
+
+surface PostFilePathSurface {
+    context path: PostFilePath
+
+    exposes:
+        path.base_dir
+        path.year
+        path.month
+        path.slug
+}
+
+surface PostCanonicalUrlSurface {
+    context url: PostCanonicalUrl
+
+    exposes:
+        url.year
+        url.month
+        url.day
+        url.slug
+}
+
+surface FrontmatterSurface {
+    context _: Frontmatter
+}
+
 entity Post {
     project: project/Project
     title: String
     slug: Slug
     excerpt: String?
     content: String?
-    status: draft | published | archived
+    status: PostStatus
     author: String?
     language: String?
     do_not_translate: Boolean
@@ -59,6 +103,15 @@ entity Post {
     updated_at: Timestamp
     published_at: Timestamp?
 
+    -- Published snapshot: copy of title/content/tags/categories/excerpt as of
+    -- the last publish. Used by changes_affect_published_content to decide when
+    -- an edit reopens a published post to draft (see ReopenPublishedPost).
+    published_title: String?
+    published_content: String?
+    published_tags: String?
+    published_categories: String?
+    published_excerpt: String?
+
     -- Relationships
     translations: PostTranslation with canonical_post = this
     linked_media: PostMediaLink with post = this
@@ -71,6 +124,10 @@ entity Post {
         -- Slug changes only allowed before first publish
     content_location: if status = published: file_path else: content
         -- Published: body in filesystem. Draft: body in DB field.
+    editor_body: if content != null: content else: read_markdown_body(file_path)
+        -- Resolver used by editors: prefer the in-DB draft content, else read
+        -- the markdown body from the post's file. Empty string when neither
+        -- exists. The same resolver applies to PostTranslation records.
 
     transitions status {
         draft -> published
@@ -104,21 +161,23 @@ rule CreatePost {
     when: CreatePostRequested(project, title, content, tags, categories, author, language, template_slug)
     let slug = Slug.generate(title ?? "untitled")
     let unique_slug = Slug.ensure_unique(slug, project)
-    ensures: Post.created(
-        project: project,
-        title: title ?? "",
-        slug: unique_slug,
-        content: content,
-        status: draft,
-        author: author,
-        language: language,
-        tags: tags ?? {},
-        categories: categories ?? {},
-        template_slug: template_slug,
-        do_not_translate: false,
-        file_path: ""
-    )
-    ensures: SearchIndexUpdated(post)
+    ensures:
+        let new_post = Post.created(
+            project: project,
+            title: title ?? "",
+            slug: unique_slug,
+            content: content,
+            status: draft,
+            author: author,
+            language: language,
+            tags: tags ?? {},
+            categories: categories ?? {},
+            template_slug: template_slug,
+            do_not_translate: false,
+            file_path: ""
+        )
+        new_post.status = draft
+        SearchIndexUpdated(new_post)
 }
 
 rule UpdatePost {
@@ -133,6 +192,13 @@ rule UpdatePost {
         -- status auto-transitions back to draft
 }
 
+rule ReopenPublishedPost {
+    when: UpdatePostRequested(post, changes)
+    requires: post.status = published
+    requires: changes_affect_published_content(changes)
+    ensures: post.status = draft
+}
+
 rule PublishPost {
     when: PublishPostRequested(post)
     requires: post.status = draft or post.status = archived
@@ -164,9 +230,43 @@ rule DeletePost {
 
 rule ArchivePost {
     when: ArchivePostRequested(post)
+    requires: post.status = draft or post.status = published
     ensures: post.status = archived
 }
 
+rule SyncPostFromFile {
+    when: SyncPostFromFileRequested(post)
+    requires: post.file_path != ""
+    -- Single-post reimport: re-reads the post's own .md file and upserts the DB
+    -- record from it (the filesystem is treated as truth for that one post).
+    -- Re-syncs the post's link graph. Errors out if the file is missing.
+    ensures: PostFieldsUpdated(post, parse_post_file(post.file_path))
+    ensures: PostLinksUpdated(post)
+}
+
+rule ImportOrphanPostFile {
+    when: ImportOrphanPostFileRequested(project, relative_path)
+    -- Imports a .md file that exists on disk but has no DB record (an orphan,
+    -- e.g. surfaced by RunMetadataDiff). Rejects non-markdown / missing files.
+    ensures:
+        let new_post = Post.created(parse_post_file(relative_path))
+        SearchIndexUpdated(new_post)
+}
+
+rule DiscardPostChanges {
+    when: DiscardPostChangesRequested(post)
+    requires: post.file_path != ""
+        -- Only posts with a published file on disk can be discarded;
+        -- a never-published draft has no file version to restore.
+    -- Re-reads the published .md file and upserts the DB record from it,
+    -- discarding unsaved draft edits.
+    ensures: post.content = null
+    ensures: post.status = published
+    ensures: PostLinksUpdated(post)
+    ensures: SearchIndexUpdated(post)
+        -- See engine_side_effects.allium DiscardPostChangesSideEffects
+}
+
 -- File format axioms
 
 invariant FrontmatterRoundtrip {
@@ -185,5 +285,5 @@ invariant DateBasedFileLayout {
 }
 
 -- Slug freeze: once published_at is set, the slug is permanently frozen.
--- This matches TypeScript behaviour: is_slug_frozen = published_at != null
+-- This follows the established bDS rule: is_slug_frozen = published_at != null
 -- Even if the post reverts to draft, the slug cannot be changed.