feat(clients): add nim-allographer client with BaraDB driver support

- Pure Nim wire protocol client (async + sync, no C FFI)
- Query Builder: fluent API, SQL generator, execution, transactions
- Schema Builder: create/alter/drop tables, column operations
- Connection pool with aging and timeout handling
- ORM integration via compile-time DB_BARADB switch
- Tests: test_open, test_query
- Documentation: README.md, PLAN_BARADB.md

clients/nim-allographer/docker/alpine/Dockerfile

@@ -0,0 +1,28 @@
+FROM nimlang/nim:1.6.2-alpine-regular
+
+RUN echo http://dl-cdn.alpinelinux.org/alpine/edge/testing >> /etc/apk/repositories
+RUN apk update && \
+    apk upgrade --no-cache && \
+    apk add --no-cache \
+        curl \
+        gcc \
+        musl-dev \
+        bsd-compat-headers \
+        openssh-client \
+        git \
+        lcov \
+        sqlite \
+        libpq \
+        mariadb-dev \
+        openssl \
+        pcre \
+        && \
+    rm /usr/lib/mysqld* -fr && \
+    rm /usr/bin/mysql* -fr
+ENV PATH $PATH:/root/.nimble/bin
+WORKDIR /root/project
+COPY ./allographer.nimble .
+RUN nimble install -y
+RUN nimble install -y \
+           bcrypt \
+           progress