Document how a new docs source is loaded and indexed

The configuration guide covered a changed CONTEXT_KIT_DOCS_SOURCES but not
an edited profile, said nothing of start's warning or of restart taking
every shared service down, and left new sources to be embedded inside the
first query. Troubleshooting had no entry for a source that never appears.

docs/troubleshooting.md

@@ -175,6 +175,22 @@ Cloudflare and other large docs sets can take significantly longer than the
 default source profile. Set `CONTEXT_KIT_DOCS_PREINDEX=1` only if you want
 startup to eagerly embed every configured source.
 
+## A New Docs Source Does Not Appear
+
+If `docs_sources` does not list a source you added, or `docs-rebuild` fails with
+`unconfigured sources`, the running docs service is still on its old source
+list. It reads the list only at startup, and `start` does not restart a running
+container; it warns instead. Restart, then index the new source:
+
+```sh
+bin/context-kit restart
+bin/context-kit docs-rebuild https://example.com/llms-full.txt
+```
+
+Edit the profile files named by `CONTEXT_KIT_DOCS_SOURCES`, not the generated
+`docs-sources.txt` under the data directory; every lifecycle command overwrites
+that file.
+
 ## Docs Sources Report Refresh Errors
 
 If `docs_sources` reports `last_error`, the service keeps the previous generation