fix(ci): webhook Docker context = repo root; pi pnpm globals in PATH

The webhook Dockerfile now references workspace-root files (pnpm-lock.yaml,
pnpm-workspace.yaml, other workspace package.json files) to run
`pnpm install --filter webhook-ingest...`. Set docker-context to repo root.

pi-coding-agent install via `pnpm add -g` requires \$PNPM_HOME/bin in PATH
(pnpm 11 uses a /bin layout, not the v10 flat layout). Add both \$PNPM_HOME
and \$PNPM_HOME/bin to PATH so corepack can find pnpm and pnpm can find its
own globals.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: FelixTJDietrich

.github/workflows/ci-docker-build.yml

@@ -81,7 +81,10 @@ jobs:
     with:
       image-name: "ls1intum/hephaestus/webhook-ingest"
       docker-file: "./server/webhook-ingest/Dockerfile"
-      docker-context: "./server/webhook-ingest"
+      # Context = repo root so the Dockerfile can COPY pnpm-lock.yaml,
+      # pnpm-workspace.yaml, and the workspace package.json files needed for
+      # `pnpm install --filter webhook-ingest...` to resolve the workspace graph.
+      docker-context: "."
       registry: "ghcr.io"
       tags: |
         ${{ github.ref_name }}

docker/agents/pi/Dockerfile

@@ -10,7 +10,10 @@ RUN apt-get update -qq && apt-get install -y --no-install-recommends git finduti
 # renovate: datasource=npm depName=@earendil-works/pi-coding-agent
 ARG PI_VERSION=0.74.1
 ENV PNPM_HOME=/usr/local/pnpm
-ENV PATH=$PNPM_HOME:$PATH
+# pnpm 11 installs globals into $PNPM_HOME/bin (the v10 flat layout was
+# deprecated); both PNPM_HOME and PNPM_HOME/bin need to be in PATH so corepack
+# can find the pnpm shim and pnpm can find the binaries it installs globally.
+ENV PATH=$PNPM_HOME/bin:$PNPM_HOME:$PATH
 RUN corepack enable && \
     corepack prepare pnpm@11.1.2 --activate && \
     pnpm add -g @earendil-works/pi-coding-agent@${PI_VERSION} && \