Make DSH agents-as-a-service browser-usable; fix probe crash-loop (#3)

* Rewrite DSH gateway for browser sessions, HTTP and WebSocket

- Replace the Flask proxy with a Starlette ASGI app (uvicorn factory),
  keeping the control plane (claims, wake/suspend, idle sweeper).
- Add HttpOnly gateway sessions and a server-side DSH launch-token
  handshake: read the token from pod logs, exchange it for a dsh-auth
  cookie, cache per (user, pod UID, Host), refresh once on 401.
- Proxy HTTP/SSE and WebSocket (/api/remote.mux) under /u/<user>/, with
  header stripping/injection, Location rewriting and wake-on-connect.
- Add a landing/signup/login page, health endpoint, pinned dependencies,
  a read-only-rootfs gateway image, 87 cluster-free tests and docs.

* Fix DSH probe crash-loop and harden gateway manifests

- Probe /favicon.svg instead of /: DSH gates / behind its launch-token
  cookie and returns 401, which made warm-pool pods crash-loop.
- Pass DSH_TRUSTED_HOSTS through the entrypoint as --trusted-host args
  for public/ingress hosts; keep localhost trusted.
- Deploy the published :gateway image, add pods/pods-log RBAC, /healthz
  probes, read-only rootfs with a /tmp emptyDir and non-root security.
- Add optional Traefik Ingress and document the prerequisites.

* Update CI, smoke tests, build tooling and docs

- Run gateway pytest/ruff and build/smoke-test the image in CI.
- Parameterize the DSH build version and pnpm version inputs.
- Exercise cookie signup, HTML proxy, WebSocket auth, suspend/wake and
  delete in run-test-kind.sh.
- Add Makefile/build.sh targets and document the architecture, handshake,
  probes, trusted hosts, troubleshooting and limitations.

---------

Co-authored-by: SREDevOpsAgents <agents@sredevops.org>

.github/workflows/multi-build.yaml

@@ -4,6 +4,17 @@ name: Build multi arch Docker Image with separate Github Runners
 
 on:
   workflow_dispatch:
+    inputs:
+      dsh_version:
+        description: "DSH git ref to build (tag or branch)"
+        required: true
+        default: dsh-v0.2.1-rc.2
+        type: string
+      pnpm_version:
+        description: "pnpm version used to build DSH"
+        required: true
+        default: "11.28.5"
+        type: string
   push:
     branches:
       - main
@@ -15,7 +26,10 @@ env:
   # The image name is derived from the GitHub repository name and the GitHub Container Registry (GHCR) URL.
   # The image name will be in the format: ghcr.io/<owner>/<repo>
   GHCR_IMAGE: ghcr.io/${{ github.repository }}
-  DSH_VERSION: dsh-v0.2.1-rc.2 #TODO: Make this configurable from workflow inputs and/or an custom Github Action
+  # workflow_dispatch inputs win; pushes to main fall back to the pinned
+  # defaults. Both values flow into the Docker build args and the image tags.
+  DSH_VERSION: ${{ inputs.dsh_version || 'dsh-v0.2.1-rc.2' }}
+  PNPM_VERSION: ${{ inputs.pnpm_version || '11.28.5' }}
 permissions:
   # Global permissions for the workflow, which can be overridden at the job level
   contents: read
@@ -130,14 +144,14 @@ jobs:
         uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7.4.0
         env:
           DOCKER_BUILDKIT: 1
-          DSH_VERSION: dsh-v0.2.1-rc.2 #TODO: Make this configurable from workflow inputs and/or an custom Github Action
-          PNPM_VERSION: 11.28.5
           DSH_PORT: 3080
         with:
           context: .
           platforms: ${{ matrix.platform }}
           labels: ${{ steps.meta.outputs.labels }}
-          build-args: DSH_VERSION=${{ env.DSH_VERSION }}
+          build-args: |
+            DSH_VERSION=${{ env.DSH_VERSION }}
+            PNPM_VERSION=${{ env.PNPM_VERSION }}
           annotations: ${{ steps.meta.outputs.annotations }}
           outputs: type=image,name=${{ env.GHCR_IMAGE }},push-by-digest=true,name-canonical=true,push=true,oci-mediatypes=true
           cache-from: type=gha,scope=${{ github.repository }}-${{ github.ref_name }}-${{ matrix.platform }}
@@ -209,8 +223,6 @@ jobs:
         # The metadata includes information such as the image name, tags, and labels.
         id: meta
         uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302 # v6.2.0
-        env:
-          DSH_VERSION: ${{ env.DSH_VERSION }}
         with:
           images: ${{ env.GHCR_IMAGE }}
           annotations: |
@@ -218,7 +230,7 @@ jobs:
           tags: |
             type=raw,value=main,enable=${{ github.ref_name == 'main' }}
             type=raw,value=latest,enable=${{ github.ref_name == 'main' }}
-            type=raw,value=${{ env.DSH_VERSION }},enable=${{ github.ref_name == 'main' }}
+            type=raw,value=${{ env.DSH_VERSION }},enable=${{ github.ref_name == 'main' || github.event_name == 'workflow_dispatch' }}
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4.4.1