fix: harden model catalog projections

docs/general/pi-configuration.md

@@ -100,7 +100,7 @@ generated/
 ├── pi/
 │   ├── models.json
 │   └── settings.json
-└── compose.model-catalog.yaml
+└── compose.models.yaml
 ```
 
 The normalized catalog is consumed by the backend. The Pi files and Compose override are boundary
@@ -117,17 +117,19 @@ tht --installation "$INSTALLATION" start
 tht --installation "$INSTALLATION" doctor
 ```
 
-After editing `modelCatalog` or provider credentials, reload the current Pi image. Restart validates
-the YAML and regenerates projections before recreating `core`:
+After editing `modelCatalog` or provider credentials, apply the complete runtime projection with
+the normal installation lifecycle, then run the Pi checks:
 
 ```bash
-tht --installation "$INSTALLATION" pi restart --yes --drain
+tht --installation "$INSTALLATION" start
 tht --installation "$INSTALLATION" pi doctor
 tht --installation "$INSTALLATION" pi test
 ```
 
-`tht pi update` changes the Pi version; it is not the configuration command. There is no
-`tht pi configure` and no separate apply command.
+`tht pi restart`, `tht pi update`, and `tht pi rollback` refuse to run while generated model
+projections differ from `modelCatalog`: those commands recreate only `core`, so they must never
+partially apply an embedding change. `tht pi update` changes the Pi version; it is not the
+configuration command. There is no `tht pi configure` and no separate apply command.
 
 ## Migrating a legacy installation
 
@@ -136,7 +138,7 @@ files, but never modifies them. Supply the facts that cannot be inferred safely
 candidate:
 
 ```bash
-tht --installation /absolute/path/legacy-installation.yaml installation migrate \
+tht --installation /absolute/path/legacy/thothii-installation.yaml installation migrate \
   --output /absolute/path/thothii-installation.v2.yaml \
   --session-default zai/glm-5.3 \
   --embedding-id ollama/qwen3-embedding:0.6b \