Align dev container Instant Client TZ data with Oracle server

[yahonda]

Summary

Apply the workaround from #292 to the dev container. CI fixed ORA-01805: possible error in date/time operation by copying the running Oracle server's timezlrg_*.dat into the Instant Client's oracore/zoneinfo/ and pointing ORA_TZFILE at it. The dev container combines gvenzl/oracle-free:latest with the Instant Client installed via the app Dockerfile and is exposed to the same drift, so it benefits from the same fix.

#301 ported the workaround by adding the docker-outside-of-docker feature and doing the copy from inside the dev container via docker exec / docker cp. That PR was closed unmerged because the feature fails to install on Dev Containers 0.459.0 against mcr.microsoft.com/devcontainers/base:trixie — Debian trixie removed moby-cli:

(!) The 'moby' option is not supported on Debian 'trixie' because 'moby-cli'
    and related system packages have been removed from that distribution.
ERROR: Feature "Docker (docker-outside-of-docker)" failed to install!

This PR moves the copy to the host, where Docker is already available. Mirrors rsim/oracle-enhanced#2799.

Changes

• .devcontainer/initializeCommand.sh (new) — pull gvenzl/oracle-free:latest, then extract $ORACLE_HOME/oracore/zoneinfo/timezlrg_*.dat from an ephemeral container into .devcontainer/tzdata/ on the host. No DB start, no readiness wait — the file ships in the image.
• .devcontainer/devcontainer.json — initializeCommand now runs the new script (it previously did the inline docker pull). No docker-outside-of-docker feature.
• .devcontainer/docker-compose.yml — bind-mount .devcontainer/tzdata read-only at /opt/tzdata inside the app service.
• .devcontainer/postCreateCommand.sh — set ORA_TZFILE from /opt/tzdata/timezlrg_*.dat and persist it via /etc/profile.d/ora-tzfile.sh so interactive shells and bundle exec runs pick it up.
• .gitignore — ignore .devcontainer/tzdata/.

No docker-outside-of-docker feature, no /var/run/docker.sock bind, and no network access during the dev container build.

Lifecycle

Matches #292 — the step is unconditional and becomes a near-zero-cost no-op once the Instant Client and the gvenzl image realign on a single TZ data version. Safe to remove together with the CI counterpart at that point.

Test plan

• Rebuild the dev container; initializeCommand logs the pulled image and the extracted timezlrg_*.dat filename.
• postCreateCommand logs "Using /opt/tzdata/timezlrg_*.dat for Instant Client TZ data."
• In a fresh terminal inside the rebuilt container, echo \$ORA_TZFILE resolves to the persisted path.
• bundle exec rake spec passes without ORA-01805 failures.

🤖 Generated with Claude Code