fix: CRLF/BOM line endings + restart policies + gitattributes

- poller/docker-entrypoint.sh: convert from CRLF+BOM to LF (UTF-8 no BOM)
  Windows saved the file with a UTF-8 BOM which made the Linux kernel
  reject the shebang with 'exec format error', crashing the poller.

- infrastructure/openbao/init.sh: same CRLF -> LF fix

- poller/Dockerfile: add sed to strip CRLF and BOM at image build time
  as a defensive measure for future Windows edits

- docker-compose.override.yml: add 'restart: on-failure' to api and poller
  so they recover from the postgres startup race (TimescaleDB restarts
  postgres after initdb, briefly causing connection refused on first boot)

- .gitattributes: enforce LF for all text/script/code files so git
  normalises line endings on checkout and prevents this class of bug

poller/Dockerfile

@@ -13,5 +13,9 @@ FROM alpine:3.21
 RUN apk add --no-cache ca-certificates iproute2
 COPY --from=builder /poller /usr/local/bin/poller
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
-RUN chmod +x /usr/local/bin/docker-entrypoint.sh
+# Strip Windows CRLF line endings and make executable (safe even if already LF)
+# Strip Windows CRLF and UTF-8 BOM if present (both break Linux shebang parsing)
+RUN sed -i 's/\r//' /usr/local/bin/docker-entrypoint.sh && \
+    sed -i '1s/^\xef\xbb\xbf//' /usr/local/bin/docker-entrypoint.sh && \
+    chmod +x /usr/local/bin/docker-entrypoint.sh
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]