fix(dev): serve web UI in debug mode — real frontend embed + data mounts in debug compose

Dockerfile.debug

@@ -1,15 +1,44 @@
-FROM golang:1.26-alpine
-WORKDIR /app
+# Copyright (C) 2026 Dcntrlized
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+# Debug build: same embedded UI as the prod Dockerfile, but the final stage
+# keeps the golang:alpine base (shell + tooling) for live debugging. Rebuild
+# this image when the frontend changes; Air handles Go hot-reload at runtime.
+
+# Stage 1: Build the UI bundle
+FROM oven/bun:1.3.9-alpine AS frontend-builder
+WORKDIR /app
+# Copy the lockfile so `bun ci` can accurately install
+COPY src/frontend/package.json src/frontend/bun.lock ./
+RUN bun ci
+COPY src/frontend/ ./
+RUN bun run build
+
+# Stage 2: Build the static Go binary
+FROM golang:1.26-alpine AS go-builder
+WORKDIR /app
 COPY src/go.mod src/go.sum ./
 RUN go mod download
 COPY src/ .
-
-# Satisfy go:embed during debug builds
-RUN mkdir -p frontend/dist && touch frontend/dist/.placeholder
-
-# Output the binary directly to /server to match the ENTRYPOINT
+# Copy the built UI into the frontend folder so go:embed finds it
+COPY --from=frontend-builder /app/dist ./frontend/dist
 RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server .
 
+# Stage 3: Debug-final image (alpine base, not scratch, for shell access)
+FROM golang:1.26-alpine
+RUN apk add --no-cache ca-certificates
+COPY --from=go-builder /server /server
 EXPOSE 8080
-ENTRYPOINT ["/server"]
+ENTRYPOINT ["/server"]