feat: add darktable web API interface with gallery, image detail, and settings screens

- Implemented main entry point for React application in `main.jsx`.
- Created `Gallery` component for displaying images with infinite scroll and pull-to-refresh functionality.
- Developed `ImageDetail` component for showing detailed information and actions for selected images.
- Added `Settings` component for configuring API connection settings.
- Integrated Vite for build and development with PWA support.
- Implemented caching strategies for API responses and image previews using Workbox.

contrib/darktable-api/server.lua

@@ -30,6 +30,56 @@ local config = require "config"
 local router = require "router"
 local api    = require "api"
 
+-- ── Static file server (PWA) ──────────────────────────────────────────────────
+
+local WEB_BUILD = script_dir .. "/web/build"
+
+local MIME = {
+  html  = "text/html; charset=utf-8",
+  js    = "application/javascript; charset=utf-8",
+  mjs   = "application/javascript; charset=utf-8",
+  css   = "text/css; charset=utf-8",
+  json  = "application/json",
+  webmanifest = "application/manifest+json",
+  png   = "image/png",
+  jpg   = "image/jpeg",
+  jpeg  = "image/jpeg",
+  svg   = "image/svg+xml",
+  ico   = "image/x-icon",
+  woff  = "font/woff",
+  woff2 = "font/woff2",
+  txt   = "text/plain; charset=utf-8",
+  map   = "application/json",
+}
+
+-- Read a file from the web build directory.  Returns data, content-type or nil.
+-- Prevents directory traversal by rejecting any path containing "..".
+local function read_static(req_path)
+  if req_path:find("%.%.", 1, true) then return nil end
+
+  -- Strip leading slash; normalise double-slashes.
+  local rel = req_path:gsub("^/+", ""):gsub("//+", "/")
+  local full = WEB_BUILD .. "/" .. rel
+
+  local f = io.open(full, "rb")
+  if not f then return nil end
+  local data = f:read("*a")
+  f:close()
+
+  local ext = rel:match("%.([^%.]+)$") or ""
+  local ct  = MIME[ext:lower()] or "application/octet-stream"
+  return data, ct
+end
+
+-- Cache headers: hashed assets get long TTL; everything else no-store.
+local function cache_header(path)
+  -- Vite fingerprints assets with a hash in the filename (e.g. index-Bx3Rk.js)
+  if path:match("/assets/") then
+    return "public, max-age=31536000, immutable"
+  end
+  return "no-store"
+end
+
 -- ── Register routes ───────────────────────────────────────────────────────────
 
 router.post("/oauth/token",              api.oauth_token)
@@ -164,16 +214,32 @@ local function handle_client(client)
     return
   end
 
+  -- API / OAuth routes take priority over static files.
   local handler, path_params = router.match(req.method, req.path)
-  if not handler then
-    write_response(client, 404, json.encode({ error = "not_found", path = req.path }))
+  if handler then
+    req.path_params = path_params or {}
+    local status, body, ct, extra = handler(req)
+    write_response(client, status, body, ct, extra)
     return
   end
 
-  req.path_params = path_params or {}
+  -- Static file serving for the PWA (GET/HEAD only).
+  if req.method == "GET" or req.method == "HEAD" then
+    local data, ct = read_static(req.path)
 
-  local status, body, ct, extra = handler(req)
-  write_response(client, status, body, ct, extra)
+    if not data then
+      -- SPA fallback: any unknown path gets index.html so client-side routing works.
+      data, ct = read_static("/index.html")
+    end
+
+    if data then
+      local extra = { ["Cache-Control"] = cache_header(req.path) }
+      write_response(client, 200, req.method == "HEAD" and "" or data, ct, extra)
+      return
+    end
+  end
+
+  write_response(client, 404, json.encode({ error = "not_found", path = req.path }))
 end
 
 -- ── Main server loop ──────────────────────────────────────────────────────────
@@ -192,8 +258,9 @@ server:settimeout(0)   -- non-blocking accept
 io.write(string.format(
   "darktable-api: listening on http://%s:%d\n" ..
   "  library : %s\n" ..
-  "  cache   : %s\n",
-  host, port, config.library_db, config.cache_dir))
+  "  cache   : %s\n" ..
+  "  web app : http://%s:%d/\n",
+  host, port, config.library_db, config.cache_dir, host, port))
 io.flush()
 
 while true do