The catalogue prepares its own schema instead of migrating at start

It brought its schema up inside its runtime, on every start. That made a schema it could not reach a
crash loop rather than a stop, with the module graph keeping a gap and nothing saying so — which is
how a whole morning's builds went unrecorded. The mesh now prepares this module's state before it
starts this version and does not start it if that failed (novox/hq ADR 0135): the work moves to an
entrypoint the image names in MESH_PREPARE, beside the entrypoints it already names.

The reason it was at start — that a step blocking the apply would block the very apply bringing the
overlay up — stopped being true when a step's failure became its module's business rather than the
machine's (ADR 0136).

modules/mesh-catalog/Dockerfile

@@ -22,7 +22,7 @@ COPY . .
 # The compiler is invoked by its real path rather than through node_modules/.bin, whose entries are
 # symlinks to a launcher that requires its library relatively — resolved away when the base image
 # was assembled.
-RUN node /app/node_modules/typescript/bin/tsc pg.d.ts store.ts index.ts tools/index.ts \
+RUN node /app/node_modules/typescript/bin/tsc pg.d.ts store.ts index.ts tools/index.ts prepare/index.ts \
       --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist
 
 # **A module may need something the base image does not carry.** The base holds what every module
@@ -48,3 +48,8 @@ COPY --from=build /deps/node_modules /app/modules/mesh-catalog/node_modules
 # to listen for what the builder announces. Serve binds the broker first, then imports these, so
 # `on()` has something to subscribe to.
 ENV MESH_TOOL_MODULES=/app/modules/mesh-catalog/dist/index.js,/app/modules/mesh-catalog/dist/tools/index.js
+
+# And what prepares this module's state, for the runtime's `prepare` mode (novox/hq ADR 0135). Named
+# here, beside the entrypoints above, because the module knows which of its files prepares its state
+# and nothing else could: the mesh asks one word and this says what answers it.
+ENV MESH_PREPARE=/app/modules/mesh-catalog/dist/prepare/index.js