.ssp serializer: include all ObjGenericComposite fields

- Make the .ssp format a complete representation of the
  document abstraction by serializing all remaining fields
  from ObjGenericComposite (only omitting ptr.* runtime
  indices which are meaningless outside the in-memory context).

- New fields added:
    .ancestors_collapsed: - collapsed level ancestor chain
    .dom_status: - DOM structure markedup tags status[8]
    .dom_status_collapsed: - DOM structure collapsed status[8]
    .heading_lev_collapsed: - collapsed heading level
    .parent_lev: - parent heading level (markup)
    .o_n_type: - object numbering type (0=ocn, 1=non, 2=bkidx)
    .is_of_type: - para/block type classification
    .attrib: - general attributes string
    .meta_lang: - block language (group/block/quote)
    .meta_syntax: - codeblock syntax from metainfo
    .sha256: - hex-encoded SHA-256 digest of object content
    .has: images_no_dim - image without dimensions flag
    .table_aligns: - column alignment array
    .table_walls: - table walls/borders flag
    .stow_link: - extracted URLs (one per line)
    .heading_lev_anchor: - heading level anchor tag
    .segment_epub: - EPUB segment anchor tag
    .heading_ancestors_text: - pipe-separated ancestor headings
    .lev4_subtoc: - sub-table-of-contents entries (one per line)
    .anchor_tag: - additional anchor tags (one per line)

- Tested against all 35 sample documents - zero failures.

  Co-Authored-By: Anthropic Claude Opus 4.6 (1M context)

1 files changed, 120 insertions, 9 deletions

diff --git a/src/sisudoc/io_out/create_abstraction_txt.d b/src/sisudoc/io_out/create_abstraction_txt.d
index 140a27d..7d0425c 100644
--- a/src/sisudoc/io_out/create_abstraction_txt.d
+++ b/src/sisudoc/io_out/create_abstraction_txt.d
@@ -53,6 +53,7 @@ module sisudoc.io_out.create_abstraction_txt;
 /+ ↓ write document abstraction as human-readable .ssp text file +/
 template spineAbstractionTxt() {
   import std.conv : to;
+  import std.digest : toHexString;
   import std.file;
   import std.path;
   import std.stdio;
@@ -201,23 +202,94 @@ template spineAbstractionTxt() {
           output ~= ".last_descendant: " ~ obj.metainfo.last_descendant_ocn.to!string;
 
         /+ ↓ ancestors (only if non-zero) +/
-        bool has_ancestors = false;
-        foreach (a; obj.metainfo.markedup_ancestors) {
-          if (a != 0) { has_ancestors = true; break; }
+        {
+          bool has_anc = false;
+          foreach (a; obj.metainfo.markedup_ancestors) {
+            if (a != 0) { has_anc = true; break; }
+          }
+          if (has_anc) {
+            string anc;
+            foreach (i, a; obj.metainfo.markedup_ancestors) {
+              if (i > 0) anc ~= " ";
+              anc ~= a.to!string;
+            }
+            output ~= ".ancestors: " ~ anc;
+          }
         }
-        if (has_ancestors) {
-          string anc;
-          foreach (i, a; obj.metainfo.markedup_ancestors) {
-            if (i > 0) anc ~= " ";
-            anc ~= a.to!string;
+        /+ ↓ collapsed ancestors (only if non-zero) +/
+        {
+          bool has_anc_c = false;
+          foreach (a; obj.metainfo.collapsed_ancestors) {
+            if (a != 0) { has_anc_c = true; break; }
+          }
+          if (has_anc_c) {
+            string anc;
+            foreach (i, a; obj.metainfo.collapsed_ancestors) {
+              if (i > 0) anc ~= " ";
+              anc ~= a.to!string;
+            }
+            output ~= ".ancestors_collapsed: " ~ anc;
+          }
+        }
+        /+ ↓ dom structure status (only if non-zero) +/
+        {
+          bool has_dom = false;
+          foreach (d; obj.metainfo.dom_structure_markedup_tags_status) {
+            if (d != 0) { has_dom = true; break; }
+          }
+          if (has_dom) {
+            string ds;
+            foreach (i, d; obj.metainfo.dom_structure_markedup_tags_status) {
+              if (i > 0) ds ~= " ";
+              ds ~= d.to!string;
+            }
+            output ~= ".dom_status: " ~ ds;
+          }
+        }
+        {
+          bool has_dom_c = false;
+          foreach (d; obj.metainfo.dom_structure_collapsed_tags_status) {
+            if (d != 0) { has_dom_c = true; break; }
+          }
+          if (has_dom_c) {
+            string ds;
+            foreach (i, d; obj.metainfo.dom_structure_collapsed_tags_status) {
+              if (i > 0) ds ~= " ";
+              ds ~= d.to!string;
+            }
+            output ~= ".dom_status_collapsed: " ~ ds;
           }
-          output ~= ".ancestors: " ~ anc;
         }
 
+        if (obj.metainfo.heading_lev_collapsed < 9)
+          output ~= ".heading_lev_collapsed: " ~ obj.metainfo.heading_lev_collapsed.to!string;
+        if (obj.metainfo.parent_lev_markup != 0)
+          output ~= ".parent_lev: " ~ obj.metainfo.parent_lev_markup.to!string;
         if (obj.metainfo.dummy_heading)
           output ~= ".dummy: true";
         if (obj.metainfo.object_number_off)
           output ~= ".ocn_off: true";
+        if (obj.metainfo.o_n_type != 0)
+          output ~= ".o_n_type: " ~ obj.metainfo.o_n_type.to!string;
+        if (obj.metainfo.is_of_type.length > 0)
+          output ~= ".is_of_type: " ~ obj.metainfo.is_of_type;
+        if (obj.metainfo.attrib.length > 0)
+          output ~= ".attrib: " ~ obj.metainfo.attrib;
+        if (obj.metainfo.lang.length > 0)
+          output ~= ".meta_lang: " ~ obj.metainfo.lang;
+        if (obj.metainfo.syntax.length > 0)
+          output ~= ".meta_syntax: " ~ obj.metainfo.syntax;
+
+        /+ ↓ sha256 digest +/
+        {
+          bool has_sha = false;
+          foreach (b; obj.metainfo.sha256) {
+            if (b != 0) { has_sha = true; break; }
+          }
+          if (has_sha) {
+            output ~= ".sha256: " ~ obj.metainfo.sha256.toHexString.to!string;
+          }
+        }
 
         /+ ↓ text attributes +/
         if (obj.attrib.indent_base != 0 || obj.attrib.indent_hang != 0)
@@ -235,6 +307,7 @@ template spineAbstractionTxt() {
           if (obj.has.inline_notes_reg) has_flags ~= "notes_reg";
           if (obj.has.inline_notes_star) has_flags ~= "notes_star";
           if (obj.has.images) has_flags ~= "images";
+          if (obj.has.image_without_dimensions) has_flags ~= "images_no_dim";
           if (has_flags.length > 0)
             output ~= ".has: " ~ has_flags.join(" ");
         }
@@ -247,8 +320,13 @@ template spineAbstractionTxt() {
             foreach (w; obj.table.column_widths) ws ~= w.to!string;
             output ~= ".table_widths: " ~ ws.join(" ");
           }
+          if (obj.table.column_aligns.length > 0) {
+            output ~= ".table_aligns: " ~ obj.table.column_aligns.join(" ");
+          }
           if (obj.table.heading)
             output ~= ".table_header: true";
+          if (obj.table.walls)
+            output ~= ".table_walls: true";
         }
 
         /+ ↓ code block properties +/
@@ -259,6 +337,13 @@ template spineAbstractionTxt() {
             output ~= ".code_linenumbers: true";
         }
 
+        /+ ↓ stow (extracted links) +/
+        if (obj.stow.link.length > 0) {
+          foreach (lnk; obj.stow.link) {
+            output ~= ".stow_link: " ~ lnk;
+          }
+        }
+
         /+ ↓ tag properties +/
         if (obj.tags.in_segment_html.length > 0)
           output ~= ".segment: " ~ obj.tags.in_segment_html;
@@ -269,6 +354,32 @@ template spineAbstractionTxt() {
           output ~= ".segment_prev: " ~ obj.tags.segname_prev;
         if (obj.tags.segname_next.length > 0)
           output ~= ".segment_next: " ~ obj.tags.segname_next;
+        if (obj.tags.heading_lev_anchor_tag.length > 0)
+          output ~= ".heading_lev_anchor: " ~ obj.tags.heading_lev_anchor_tag;
+        if (obj.tags.segment_anchor_tag_epub.length > 0)
+          output ~= ".segment_epub: " ~ obj.tags.segment_anchor_tag_epub;
+        /+ ↓ heading ancestors text +/
+        {
+          bool has_hat = false;
+          foreach (h; obj.tags.heading_ancestors_text) {
+            if (h.length > 0) { has_hat = true; break; }
+          }
+          if (has_hat) {
+            output ~= ".heading_ancestors_text: " ~ obj.tags.heading_ancestors_text.join("|");
+          }
+        }
+        /+ ↓ lev4 subtoc +/
+        if (obj.tags.lev4_subtoc.length > 0) {
+          foreach (st; obj.tags.lev4_subtoc) {
+            output ~= ".lev4_subtoc: " ~ st;
+          }
+        }
+        /+ ↓ anchor tags +/
+        if (obj.tags.anchor_tags.length > 0) {
+          foreach (at; obj.tags.anchor_tags) {
+            output ~= ".anchor_tag: " ~ at;
+          }
+        }
 
         /+ ↓ text content +/
         if (obj.text.length > 0) {