Fix OKF folder-note link roundtrip (#110)

Author: Ar9av

.skills/wiki-export/SKILL.md

@@ -337,6 +337,8 @@ Reuse the node list from Step 1 (with any active project/visibility filters alre
    - `[[concepts/transformers]]` → `[<target title>](<file-relative path>.md)`, e.g. from `entities/foo.md` a link to `concepts/transformers` becomes `[Transformer Architecture](../concepts/transformers.md)`. Link text = the target page's `title` (fall back to the target id if unknown).
    - `[[target|display]]` → `[display](<rel path>.md)`.
    - Use **file-relative** paths (`../concepts/x.md`), **never** `/`-absolute — `/`-rooted links break GitHub rendering. (This matches knowledge-catalog's own production agent.)
+   - Compute that relative path from the **target file path**, not the bare page id: normalize the wikilink target to its page id, append `.md`, then compute `relpath(<target-file>, <source-file-dir>)`. Never call `relpath()` on the id before adding `.md`.
+   - This is required for the common "folder note" layout where a page id exists both as a file and as a directory prefix, e.g. `projects/social-twitter.md` plus `projects/social-twitter/...`. From `projects/social-twitter/concepts/mem0-memory-analysis.md`, a link to `[[projects/social-twitter]]` must export to `../../social-twitter.md`, not `...md`.
    - Resolve link targets with the same normalization used in Step 1 (lowercase, spaces→hyphens, strip `.md`). Handle unresolved targets by form, so forward-references survive the round-trip:
      - **Resolves to an in-scope page** → relative markdown link to it.
      - **Path-form target** (contains a `/`, e.g. `[[concepts/attention-mechanism]]`) with **no page yet**, and not excluded by an active filter → still emit the relative markdown link. OKF §5.3 treats a missing target as not-yet-written knowledge, and keeping the link makes the user's forward-references lossless on re-import. (Verified on st3ve: dropping these silently deleted real `[[wikilinks]]`.)

.skills/wiki-import/SKILL.md

@@ -180,6 +180,7 @@ Walk the bundle directory tree. For each `.md` file that is **not** a reserved f
    - Carry through any other preserved extension keys verbatim (`relationships`, `lifecycle`, `tier`, `base_confidence`, …). These make the round-trip lossless.
 4. **Reverse-transform body links** — markdown links that point at `.md` paths become wikilinks (this restores both real cross-links and forward-references the exporter preserved per `wiki-export` Step 3.5):
    - `[text](../concepts/transformers.md)` or `[text](/concepts/transformers.md)` → resolve the path (relative to this file's dir, or bundle-root for `/`-absolute) to a concept id → `[[concepts/transformers]]`, or `[[concepts/transformers|text]]` when `text` differs from the target's title. The target's title comes from the bundle page when it exists; otherwise compare against the last path segment.
+   - Treat the markdown target as a **file path first**: normalize the `.md` path relative to the current file, then strip the trailing `.md` from the resolved file path to recover the page id. Do not try to infer the id from directory traversal segments before resolving the full file path. This preserves round-trips for folder-note layouts like `projects/social-twitter.md` plus `projects/social-twitter/...`, where `../../social-twitter.md` must restore to `projects/social-twitter`.
    - This applies **even when the target page is not in the bundle** — a path-form link to a not-yet-written page round-trips back to a dangling `[[wikilink]]` (Obsidian supports these; OKF §5.3 expects them). Do not leave it as a markdown link.
    - When `OBSIDIAN_LINK_FORMAT=markdown` is set in config, **keep** markdown links (just rewrite the path to be vault-relative); do not convert to wikilinks.
    - Leave external `http(s)://` links and `# Citations` sections untouched.

tests/test_okf_same_name_link_roundtrip.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import posixpath
+import unittest
+
+
+def export_okf_link_path(source_file: str, target_id: str) -> str:
+    """Model wiki-export Step 3.5's required target-file relpath behavior."""
+    source_dir = posixpath.dirname(source_file)
+    target_file = f"{target_id}.md"
+    return posixpath.relpath(target_file, source_dir)
+
+
+def import_okf_link_target(source_file: str, markdown_target: str) -> str:
+    """Model wiki-import Step 4-OKF's .md path -> page id reversal."""
+    source_dir = posixpath.dirname(source_file)
+    resolved = posixpath.normpath(posixpath.join(source_dir, markdown_target))
+    if not resolved.endswith(".md"):
+        raise ValueError(f"expected markdown file path, got: {markdown_target}")
+    return resolved[:-3]
+
+
+class OkfSameNameLinkRoundTripTest(unittest.TestCase):
+    def test_child_to_parent_uses_target_file_path(self) -> None:
+        source = "projects/social-twitter/concepts/mem0-memory-analysis.md"
+        target_id = "projects/social-twitter"
+
+        exported = export_okf_link_path(source, target_id)
+
+        self.assertEqual(exported, "../../social-twitter.md")
+
+    def test_child_to_parent_round_trips_back_to_parent_id(self) -> None:
+        source = "projects/social-twitter/concepts/mem0-memory-analysis.md"
+        markdown_target = "../../social-twitter.md"
+
+        restored = import_okf_link_target(source, markdown_target)
+
+        self.assertEqual(restored, "projects/social-twitter")
+
+    def test_naive_id_relpath_is_the_buggy_case(self) -> None:
+        source_dir = "projects/social-twitter/concepts"
+        target_id = "projects/social-twitter"
+
+        buggy = posixpath.relpath(target_id, source_dir) + ".md"
+
+        self.assertEqual(buggy, "...md")
+
+
+if __name__ == "__main__":
+    unittest.main()