docs(issues): add issue 1748 spec

Author: josecelano

docs/issues/1748-remove-redundant-compose-step-from-container-workflow.md

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+# Remove Redundant Compose Step From Container Workflow
+
+## Overview
+
+The `container` workflow still includes a `Compose` step that runs:
+
+- `docker compose -f compose.qbittorrent-e2e.sqlite3.yaml build`
+- `docker compose -f compose.qbittorrent-e2e.mysql.yaml build`
+- `docker compose -f compose.qbittorrent-e2e.postgresql.yaml build`
+
+This step no longer provides unique verification value and adds significant CI time.
+
+- GitHub issue: [#1748](https://github.com/torrust/torrust-tracker/issues/1748)
+- Affected workflow: [`.github/workflows/container.yaml`](../../.github/workflows/container.yaml)
+- Related workflow: [`.github/workflows/testing.yaml`](../../.github/workflows/testing.yaml)
+
+## Background
+
+Historically, the `Compose` step in `container.yaml` was used as a lightweight check to ensure
+compose configuration remained buildable.
+
+The project now has dedicated compose runtime coverage in `testing.yaml` (`docker-e2e` job):
+
+- `e2e_tests_runner --tracker-image torrust-tracker:e2e-local --skip-build`
+- `qbittorrent_e2e_runner --tracker-image torrust-tracker:e2e-local --skip-build --db-driver sqlite3`
+- `qbittorrent_e2e_runner --tracker-image torrust-tracker:e2e-local --skip-build --db-driver mysql`
+- `qbittorrent_e2e_runner --tracker-image torrust-tracker:e2e-local --skip-build --db-driver postgresql`
+
+As a result, compose files are actively validated by tests that matter at runtime.
+
+## Problem
+
+The `Compose` step in `container.yaml` is redundant and expensive:
+
+- It performs only extra build invocations, not runtime verification.
+- It can trigger repeated image builds in the same job.
+- It increases CI duration in the `container` workflow substantially.
+- It makes Docker layer-cache behavior harder to reason about in workflow diagnostics.
+
+## Proposed Change
+
+Remove the `Compose` step from the `test` job in `.github/workflows/container.yaml`.
+
+Keep the existing `Build` + `Inspect` steps in `container.yaml` for image build integrity checks,
+while retaining compose runtime validation in `testing.yaml` (`docker-e2e`).
+
+## Goals
+
+- [ ] Remove the `Compose` step from `.github/workflows/container.yaml`.
+- [ ] Keep `container` workflow matrix build behavior unchanged (`debug` and `release`).
+- [ ] Keep compose runtime verification in `.github/workflows/testing.yaml`.
+- [ ] Confirm reduced CI duration for `container` workflow after merge.
+
+## Non-Goals
+
+- Changing compose files used by E2E tests.
+- Modifying test logic in `e2e_tests_runner` or `qbittorrent_e2e_runner`.
+- Altering publish jobs in `container.yaml`.