Mirror the URL space in the frontend build layout

Build with assetsDir: '_/assets' so hashed assets land under
frontend-build/_/assets/ and favicon.ico (from frontend/public) at the
build root, then serve the whole build directory at the site root again
(frontend.route(app, "/"), cached="/_/assets/"). The explicit
favicon route is dropped — the Frontend serves it as an ordinary
unhashed (no-cache) file. Manifest paths now carry the _/assets/
prefix, so views.py only prepends a slash.

AGENTS.md

@@ -21,15 +21,17 @@ not for the public pages. See `docs/design-principles.md` for the design.
   - `app.py` — the FastAPI app. FastAPI's built-in API docs are disabled
     (`docs_url`/`redoc_url`/`openapi_url=None`) because `/docs` belongs to
     our content. Our own routes (content pages, `/_/api/...`, `/_/f/...`,
-    `/_/assets/...`, `/_/admin`) are registered BEFORE `frontend.route(app, "/_/assets")` is
+    `/_/admin`) are registered BEFORE `frontend.route(app, "/")` is
     called: fastapi-vue inserts its file routes at the position where
     `route()` was called (during `load()` in the lifespan), so anything
     defined earlier wins. The one exception is the content catch-all
     `/{path:path}`, registered AFTER `frontend.route()` so that built
     frontend assets still take priority over content slugs. The `Frontend`
     is constructed with `spa=False` explicitly: it only serves the built
-    asset files under `/_/assets/` without a catch-all; an `index.html` in the build
-    would become a `/_/assets/` route, so leave it out of the build to keep `/` ours.
+    files without a catch-all. The build mirrors the URL space — hashed
+    immutable assets under `/_/assets/`, `favicon.ico` at the site root —
+    and an `index.html` in the build would become a `/` route, so leave it
+    out of the build to keep `/` ours.
   - `data.py` — msgspec Structs for the kanta database. The site structure
     is a tree: `Data.menu` maps top-level slugs to `Node`s, each with
     `children` keyed by slug — the URL path is the slug chain. The front
@@ -108,7 +110,9 @@ not for the public pages. See `docs/design-principles.md` for the design.
   In dev, modules load from the Vite dev server (`PAGERITE_VITE_URL`),
   in prod from the hashed build assets resolved via
   `frontend-build/.vite/manifest.json`. `vite.config.js` builds with
-  `manifest: true`, `assetsDir: ''` and JS inputs (`src/main.js` and
+  `manifest: true`, `assetsDir: '_/assets'` (so the build mirrors the URL
+  space; `frontend/public/favicon.ico` lands at the build root and is
+  served at `/favicon.ico`) and JS inputs (`src/main.js` and
   `src/pagerite.js`) so no `index.html` ends up in the build (it would shadow
   `/`). All outputs are ES modules. vite-plugin-fastapi.js has an
   auto-upgrade marker — edit `vite.config.js`, not the plugin.

docs/design-principles.md

@@ -30,7 +30,8 @@ evolves.
   (`/docs/design-principles`-style). The URL space is the author's, so
   reserved prefixes must be kept few and deliberate: everything internal
   lives under `/_/` (the API at `/_/api/`, uploaded files at `/_/f/`, built
-  assets at `/_/assets/`, and the admin shell at `/_/admin`).
+  assets at `/_/assets/`, and the admin shell at `/_/admin`). The only
+  other reserved root path is `/favicon.ico`, served from the build.
 - **Single user, trusted author.** No auth concerns in the core design.
   Everything published is public; only editing tools will later sit behind
   access control (external SSO when that time comes). The author is trusted
@@ -75,7 +76,8 @@ evolves.
   **per-page configurable**: `Node.banner` holds an arbitrary trusted HTML
   snippet (an image, a styled div, canvas + script — anything), resolved by
   walking up the node's ancestors to the front page; when nothing in the
-  chain sets one, the default `/_/assets/banner-*.svg` artwork shows.
+  chain sets one, the default `banner.svg` artwork (inlined into the
+  stylesheet by the build) shows.
 - **Fetch-navigation.** Links are plain `<a href>`; a small script
   (`frontend/src/pagerite.js`) intercepts same-origin clicks, fetches the
   page, and swaps the `#page-banner`, `#nav`, `#sidebar` and `#main` regions

frontend/vite.config.js

@@ -27,10 +27,11 @@ export default defineConfig({
     },
   },
   build: {
-    // Emit hashed assets at the root of frontend-build so the backend can
-    // serve them under /_/assets/{file} without a nested /assets directory.
+    // Mirror the URL space in the build output: hashed files land under
+    // frontend-build/_/assets/ and the Frontend serves the build directory
+    // at the site root (frontend/public/favicon.ico -> /favicon.ico).
     manifest: true,
-    assetsDir: '',
+    assetsDir: '_/assets',
     rollupOptions: {
       input: {
         main: fileURLToPath(new URL('./src/main.js', import.meta.url)),

pagerite/app.py

@@ -1,7 +1,7 @@
 """FastAPI application: server-rendered content pages plus Vue assets.
 
 Route ordering matters: our routes are defined before
-``frontend.route(app, "/_/assets")`` is called, so they take priority over
+``frontend.route(app, "/")`` is called, so they take priority over
 the asset routes that fastapi-vue inserts at that position during ``load()``.
 The content catch-all (``/{path:path}``) is defined last, so built
 frontend assets still win over content slugs; anything unmatched falls
@@ -21,7 +21,7 @@ from pathlib import Path
 
 import blake3
 from fastapi import FastAPI, HTTPException, Request, WebSocket, WebSocketDisconnect
-from fastapi.responses import FileResponse, HTMLResponse, RedirectResponse, Response
+from fastapi.responses import HTMLResponse, RedirectResponse, Response
 from fastapi_vue import Frontend
 from kanta import Kanta
 from pydantic import BaseModel
@@ -45,11 +45,11 @@ DB_PATH = os.getenv("PAGERITE_DB", "pagerite.kanta")
 data = Data()
 kanta = Kanta(DB_PATH, data)
 
-# Vue build assets served under /_/assets/, no SPA catch-all (assets only).
-# With assetsDir: '', all files are emitted at the build root, so cached="/"
-# marks every built file immutable.
+# Vue build served at the site root, no SPA catch-all (assets only). The
+# build mirrors the URL space: hashed, immutable files live under
+# /_/assets/ (assetsDir: '_/assets'), the favicon at /favicon.ico.
 BUILD_DIR = Path(__file__).with_name("frontend-build")
-frontend = Frontend(BUILD_DIR, spa=False, cached="/")
+frontend = Frontend(BUILD_DIR, spa=False, cached="/_/assets/")
 
 
 def _hash_name(body: bytes, orig: str) -> str:
@@ -475,23 +475,15 @@ async def admin() -> HTMLResponse:
     return HTMLResponse(views.render_editor())
 
 
-@app.get("/favicon.ico")
-async def favicon() -> FileResponse:
-    """Serve the favicon copied from frontend/public by the Vite build."""
-    file = BUILD_DIR / "favicon.ico"
-    if not file.is_file():
-        raise HTTPException(404)
-    return FileResponse(file)
-
-
 @app.get("/")
 async def front_page(request: Request) -> Response:
     """Render the front page (slug path "")."""
     return await show_page(request, "")
 
 
-# Vue build asset routes are inserted at this position during load().
-frontend.route(app, "/_/assets")
+# Vue build asset routes are inserted at this position during load(): the
+# build mirrors the URL space (/_/assets/*, /favicon.ico at the root).
+frontend.route(app, "/")
 
 
 @app.get("/{path:path}", response_model=None)

pagerite/views.py

@@ -243,8 +243,9 @@ def _page_assets() -> tuple[list[str], list[str]]:
         )
     manifest = json.loads((BUILD / ".vite/manifest.json").read_text())
     entry = manifest["src/pagerite.js"]
-    styles = [f"/_/assets/{css}" for css in entry.get("css", [])]
-    return [f"/_/assets/{entry['file']}"], styles
+    # Manifest paths already carry the _/assets/ prefix (assetsDir).
+    styles = [f"/{css}" for css in entry.get("css", [])]
+    return [f"/{entry['file']}"], styles
 
 
 def _editor_assets() -> tuple[list[str], list[str]]:
@@ -260,8 +261,8 @@ def _editor_assets() -> tuple[list[str], list[str]]:
         )
     manifest = json.loads((BUILD / ".vite/manifest.json").read_text())
     entry = manifest["src/main.js"]
-    styles = [f"/_/assets/{css}" for css in entry.get("css", [])]
-    return [f"/_/assets/{entry['file']}"], styles
+    styles = [f"/{css}" for css in entry.get("css", [])]
+    return [f"/{entry['file']}"], styles
 
 
 def render_editor() -> str: