Replace shared_lib submodule with shared for decoupling deploy

- Swap shared_lib submodule → shared (tracking decoupling branch)
- Dockerfile: shared_lib/ → shared/, remove bp symlink hack
- CI: trigger on decoupling branch, use dynamic ref_name

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -16,14 +16,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
       postgresql-client \
     && rm -rf /var/lib/apt/lists/*
 
-COPY shared_lib/requirements.txt ./requirements.txt
+COPY shared/requirements.txt ./requirements.txt
 RUN pip install -r requirements.txt
 
 COPY . .
 
-# Link app blueprints into the shared library's namespace
-RUN rm -rf /app/shared_lib/suma_browser/app/bp && ln -s /app/bp /app/shared_lib/suma_browser/app/bp
-
 # ---------- Runtime setup ----------
 COPY entrypoint.sh /usr/local/bin/entrypoint.sh
 RUN chmod +x /usr/local/bin/entrypoint.sh