Add personal Markdown mount CLI

docs/source-models.md

@@ -52,7 +52,8 @@ Flow:
 ```text
 personal Markdown or Obsidian vault
   -> selected include paths
-  -> projection registry
+  -> local mount registry
+  -> authenticated projection request
   -> read-only AFFiNE docs
 ```
 
@@ -62,6 +63,19 @@ Why this exists:
 - It avoids forcing everyone into one giant shared repo.
 - It lets people publish useful slices without adopting a new editor.
 
+CLI flow:
+
+```sh
+section0-docs auth login
+section0-docs mount add research ~/Documents/Obsidian/Research
+section0-docs mount plan research
+section0-docs mount sync research
+```
+
+`mount plan` prints the exact payload before it is sent. `mount status` shows
+the local declaration and the last sync receipt. `mount unmount` removes the
+projected AFFiNE docs for that namespace without touching the source folder.
+
 ## Choosing Between Them
 
 Use Git-backed docs when the document itself is a shared artifact.