fix(report): don't emit dangling [[_COMMUNITY_*]] wikilinks by default (#1712)

GRAPH_REPORT.md rendered the Community Hubs section as Obsidian wikilinks, but
the `_COMMUNITY_*.md` notes they target are only created by the opt-in
`--obsidian` export — and the report is written at build time, before any export
runs. So on a default run every link dangled: inside an Obsidian vault they
spawned phantom `_COMMUNITY_*` nodes in the graph view, and outside Obsidian they
rendered as literal brackets that navigate nowhere.

`generate()` now takes `obsidian: bool = False`; by default the hubs render as a
plain list, and the wikilink form is emitted only when a caller opts in. The
Obsidian export's own community notes already cross-link each other, so the vault
stays navigable without the report's links. Mirrors the #1444/#1465 portability
fix that was applied to `export wiki`.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

graphify/report.py

@@ -82,6 +82,7 @@ def generate(
     min_community_size: int = 3,
     built_at_commit: str | None = None,
     learning: dict | None = None,
+    obsidian: bool = False,
 ) -> str:
     today = date.today().isoformat()
 
@@ -140,14 +141,21 @@ def generate(
             "- Run `graphify update .` after code changes (no API cost).",
         ]
 
-    # Community hub navigation - links to _COMMUNITY_*.md files in the Obsidian vault.
-    # Without these, GRAPH_REPORT.md is a dead-end and the vault splits into disconnected components.
+    # Community hub navigation. The `_COMMUNITY_*.md` notes these wikilinks target
+    # are only created by the opt-in `--obsidian` export, and the report is written
+    # at build time (before any export runs), so emitting wikilinks by default left
+    # every link dangling — polluting an Obsidian vault's graph view and rendering as
+    # literal brackets everywhere else (#1712). Emit wikilinks only when the caller
+    # signals Obsidian output; otherwise a plain list, which navigates nowhere-to-break.
     if non_empty:
         lines += ["", "## Community Hubs (Navigation)"]
         for cid in non_empty:
             label = community_labels.get(cid, f"Community {cid}")
-            safe = _safe_community_name(label)
-            lines.append(f"- [[_COMMUNITY_{safe}|{label}]]")
+            if obsidian:
+                safe = _safe_community_name(label)
+                lines.append(f"- [[_COMMUNITY_{safe}|{label}]]")
+            else:
+                lines.append(f"- {label}")
 
     lines += [
         "",

tests/test_report.py

@@ -135,3 +135,22 @@ def test_import_cycles_section_absent_for_documents_only_corpus():
     tokens = {"input": 0, "output": 0}
     report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project")
     assert "## Import Cycles" not in report
+
+
+def test_report_hubs_are_plain_text_by_default():
+    # #1712: without --obsidian the _COMMUNITY_*.md notes don't exist, so wikilinks
+    # would dangle (and pollute an Obsidian vault's graph view). Default to plain text.
+    G, communities, cohesion, labels, gods, surprises, detection, tokens = make_inputs()
+    labels = {cid: f"Widget {cid}" for cid in communities}
+    report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project", min_community_size=1)
+    assert "## Community Hubs (Navigation)" in report
+    assert "[[_COMMUNITY_" not in report, "must not emit dangling Obsidian wikilinks by default (#1712)"
+    assert any(f"- Widget {cid}" in report for cid in communities)
+
+
+def test_report_hubs_use_wikilinks_when_obsidian():
+    # The opt-in path keeps the vault-navigable wikilink form.
+    G, communities, cohesion, labels, gods, surprises, detection, tokens = make_inputs()
+    labels = {cid: f"Widget {cid}" for cid in communities}
+    report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project", min_community_size=1, obsidian=True)
+    assert "[[_COMMUNITY_" in report