Improve collaborator setup UX

docs/projection-operations.md

@@ -30,6 +30,17 @@ git push
 The operator keeps a separate checkout so projection never depends on a
 collaborator's dirty working tree.
 
+Nice wrapper:
+
+```sh
+/Users/virgil/Developer/rta/tmp/markdown-projection-gitea/collaborator-checkout/rta-mock-docs/scripts/project-rta-mock-docs.sh
+```
+
+It pulls the projector checkout, checks it is clean, and runs the AFFiNE
+projection command.
+
+Manual equivalent:
+
 ```sh
 git -C /Users/virgil/Developer/rta/tmp/markdown-projection-gitea/projector-checkout/rta-mock-docs pull --ff-only
 ```
@@ -52,14 +63,34 @@ nix develop --command bash -lc 'scripts/ops/sync-obsidian-affine.rb \
   --apply'
 ```
 
-Expected healthy result:
+Expected healthy result currently includes five docs:
 
 ```text
-docs:       3
+docs:       5
 mark stale: 0
 mode:       one-way read-only AFFiNE docs
 ```
 
+## Push-To-Projection Automation
+
+Pushing to `main` can trigger sync, but it should be implemented as a small
+projection worker, not as a Gitea container hook.
+
+Preferred shape:
+
+```text
+Gitea push webhook
+  -> RTA projection worker endpoint
+  -> pull projector checkout
+  -> validate clean source
+  -> run projection
+  -> emit logs/receipt
+```
+
+This keeps Gitea as Git infrastructure and keeps projection policy in RTA. A
+server-side Git hook inside the Gitea container would be harder to observe,
+harder to recover, and too tightly coupled to the packaged app internals.
+
 ## Rule Of Thumb
 
 If the source repo changes, pull the projector checkout and run projection.