decouple abstraction phase1:2

phase1 step2: move SSP serialiser into sisudoc.abstraction package

git mv src/sisudoc/io_out/create_abstraction_txt.d to
  src/sisudoc/abstraction/ssp.d

Module rename: sisudoc.io_out.create_abstraction_txt
  -> sisudoc.abstraction.ssp

Completes phase1: after this commit the sisudoc.abstraction package has
zero outgoing edges into sisudoc.io_out. The library produces both the
in-memory document object model AND the .ssp text serialisation without
referencing any output-side module.

The serialiser previously imported sisudoc.io_out.paths_output for the
single purpose of constructing the .ssp output path. That import is
dropped; the path construction is inlined as three lines of std.path
(chainPath / asNormalizedPath / array) producing
  <output_path>/<language>/abstraction/<doc_uid_out>.ssp
- byte-for-byte the same path the previous spineOutPaths!() call
produced.

Updated:
- src/sisudoc/abstraction/ssp.d - module decl + inline path
- src/sisudoc/abstraction/package.d - public import .ssp
- src/sisudoc/spine.d - import sisudoc.abstraction.ssp (x2)

Completes decouple abstraction phase1

(assisted by Claude-Code)

3 files changed, 10 insertions, 7 deletions

diff --git a/src/sisudoc/abstraction/package.d b/src/sisudoc/abstraction/package.d
index 74110f6..645a514 100644
--- a/src/sisudoc/abstraction/package.d
+++ b/src/sisudoc/abstraction/package.d
@@ -83,3 +83,4 @@ module sisudoc.abstraction;
 @safe:
 public import sisudoc.meta.metadoc;          // spineAbstraction (A-layer)
 public import sisudoc.meta.metadoc_from_src; // docAbstraction   (B-layer)
+public import sisudoc.abstraction.ssp;       // spineAbstractionTxt (.ssp)
diff --git a/src/sisudoc/io_out/create_abstraction_txt.d b/src/sisudoc/abstraction/ssp.d
index af98f61..6eecef0 100644
--- a/src/sisudoc/io_out/create_abstraction_txt.d
+++ b/src/sisudoc/abstraction/ssp.d
@@ -47,7 +47,7 @@
     [https://git.sisudoc.org/]
 
 +/
-module sisudoc.io_out.create_abstraction_txt;
+module sisudoc.abstraction.ssp;
 @safe:
 
 /+ ↓ write document abstraction as human-readable .ssp text file +/
@@ -59,7 +59,6 @@ template spineAbstractionTxt() {
   import std.stdio;
   import std.string;
   import std.array;
-  import sisudoc.io_out.paths_output;
 
   void spineAbstractionTxt(D)(D doc) {
     auto doc_abstraction = doc.abstraction;
@@ -408,9 +407,12 @@ template spineAbstractionTxt() {
     }
 
     /+ ↓ write to file +/
-    auto out_pth = spineOutPaths!()(doc_matters.output_path, doc_matters.src.language);
-    string base_dir = "abstraction";
-    string base_pth = ((out_pth.output_base.chainPath(base_dir)).asNormalizedPath).array;
+    /+ path: <output_path>/<language>/abstraction/<doc_uid_out>.ssp +/
+    string out_root = (doc_matters.output_path.length > 0)
+      ? doc_matters.output_path : "";
+    string base_pth = (out_root
+      .chainPath(doc_matters.src.language, "abstraction")
+      .asNormalizedPath).array;
     try {
       if (!exists(base_pth)) {
         base_pth.mkdirRecurse;
diff --git a/src/sisudoc/spine.d b/src/sisudoc/spine.d
index b00469a..a47c6db 100755
--- a/src/sisudoc/spine.d
+++ b/src/sisudoc/spine.d
@@ -1326,7 +1326,7 @@ string program_name = "spine";
           }
           /+ ↓ document abstraction text representation +/
           if (doc.matters.opt.action.show_abstraction) {
-            import sisudoc.io_out.create_abstraction_txt;
+            import sisudoc.abstraction.ssp;
             spineAbstractionTxt!()(doc);
           }
           /+ ↓ document abstraction sqlite database +/
@@ -1435,7 +1435,7 @@ string program_name = "spine";
           }
           /+ ↓ document abstraction text representation +/
           if (doc.matters.opt.action.show_abstraction) {
-            import sisudoc.io_out.create_abstraction_txt;
+            import sisudoc.abstraction.ssp;
             spineAbstractionTxt!()(doc);
           }
           /+ ↓ document abstraction sqlite database +/