build: a clone compiles before the frontend is built

rust-embed refused to derive without `web/dist`, so on a fresh clone
`cargo check`, `cargo test` and rust-analyzer failed with a derive error that
did not say what was missing. With `allow_missing` the embed is empty until
the frontend is built, and the handler gives the answer it already had for
that case, "frontend not built". The release build is unchanged once
`web/dist` is there, which `make build`, the Dockerfile and CI all see to.

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: oven-sh/setup-bun@v2
-      # The binary embeds web/dist, so nothing compiles before the frontend is built.
+      # Built first so the binary under test embeds the app it ships with.
       - name: frontend
         working-directory: web
         run: |

README.md

@@ -91,8 +91,8 @@ make dev-web   # vite dev server on :4243, proxying /api to :4242
 ```
 
 In debug builds the binary reads `web/dist` from disk, so `cargo run` alone also
-works once the frontend has been built at least once — and not before: the
-binary embeds `web/dist`, so a fresh clone builds the frontend first.
+works once the frontend has been built at least once. Before that it compiles,
+tests and runs the API, and answers every page with "frontend not built".
 
 `make check` runs what CI runs: format, clippy, the tests, svelte-check, and a
 check that the generated wiki pages are current. The wiki is written in

docs/wiki/Development.md

@@ -7,9 +7,11 @@ make dev-api   # cargo run, serving the API on :4242
 make dev-web   # vite on :4243, proxying /api to :4242
 ```
 
-Open <http://127.0.0.1:4243>. The Rust build embeds `web/dist`, so build the
-frontend once (`cd web && bun install && bun run build`) before the first
-`cargo build`; a debug build reads `web/dist` from disk after that.
+Open <http://127.0.0.1:4243>. The release binary embeds `web/dist`, and a
+debug build reads it from disk, so build the frontend once
+(`cd web && bun install && bun run build`) for `cargo run` alone to serve the
+app. Without it the Rust side still compiles and tests, and the pages answer
+"frontend not built".
 
 Point `WORKSPACE_DATA_DIR` at a throwaway directory while trying things, so the
 real data stays out of it.
@@ -57,8 +59,8 @@ block at the bottom.
 
 `.github/workflows/ci.yml` runs on every push and pull request:
 
-- **rust**: builds the frontend (the binary embeds it), then format, clippy
-  and the tests;
+- **rust**: builds the frontend, so the tests see the app the binary ships,
+  then format, clippy and the tests;
 - **web**: svelte-check;
 - **docs**: checks that the generated wiki pages are up to date and that every
   link between the pages resolves.

src/static_files.rs

@@ -5,9 +5,12 @@ use axum::{
 use rust_embed::Embed;
 
 /// The built Svelte app. In debug builds rust-embed reads from disk, so a
-/// `vite build --watch` next to `cargo run` is enough for iteration.
+/// `vite build --watch` next to `cargo run` is enough for iteration. A clone
+/// that has not built the frontend yet still compiles, tests and checks; it
+/// serves the "frontend not built" answer below until it has.
 #[derive(Embed)]
 #[folder = "$CARGO_MANIFEST_DIR/web/dist"]
+#[allow_missing = true]
 struct Assets;
 
 pub async fn handler(uri: Uri) -> Response {