Fix #188: collect_files() now respects .graphifyignore; fix #195: skill.md requires general-purpose subagent type for extraction dispatch

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

graphify/skill-opencode.md

@@ -301,10 +301,12 @@ Output exactly this JSON (no other text):
 **Step B3 - Collect, cache, and merge**
 
 Wait for all subagents. For each result:
-- If a subagent returned valid JSON with `nodes` and `edges`, include it and save each file's nodes/edges to the cache
+- Check that `graphify-out/.graphify_chunk_NN.json` exists on disk — this is the success signal
+- If the file exists and contains valid JSON with `nodes` and `edges`, include it and save to cache
+- If the file is missing, the subagent was likely dispatched as read-only (Explore type) — print a warning: "chunk N missing from disk — subagent may have been read-only. Re-run with general-purpose agent." Do not silently skip.
 - If a subagent failed or returned invalid JSON, print a warning and skip that chunk - do not abort
 
-If more than half the chunks failed, stop and tell the user.
+If more than half the chunks failed or are missing, stop and tell the user to re-run and ensure `subagent_type="general-purpose"` is used.
 
 Save new results to cache:
 ```bash