chore: bump container image to sha-bbc958b

[DavidCozens]

Purpose

Picks up the FatFs R0.16 swap from CppUTestFreertosDocker#1. Plus-FAT is gone from the image; FatFs is now at `/opt/fatfs` with `FATFS_PATH` set.

Prerequisite for #270 (S08.05 — Store-and-forward on FatFs), which targets FatFs as its embedded persistent-store backend.

Change Description

Per the `docs/containers.md` "Updating an image" checklist:

• `.devcontainer/docker-compose.yml` — `freertos-host` and `freertos-target` services.
• `.github/workflows/ci.yml` — `build-freertos-host-tdd` and `build-freertos-target` jobs.
• `ci/docker-compose.bdd.yml` — `behave-freertos` service.
• `docs/containers.md` — both image rows; "Plus-FAT" → "FatFs" in the env-vars text.
• `Platform/FreeRtos/CMakeLists.txt` — drops the Plus-FAT mention from the header-configured rationale, since Plus-FAT is no longer in the image. The header-configured INTERFACE-library pattern still applies to FreeRTOS itself; FatFs (when S08.05 adds `Platform/FatFs/`) will be its own peer pack with its own `ffconf.h` rationale.

DEVLOG entries from 2026-04-21 (S08.01) that historically mention "Plus-FAT" are left alone — those describe the state at the time and shouldn't be rewritten.

Test Evidence

Pre-push verification on the new image:

```
$ docker run --rm ghcr.io/davidcozens/cpputest-freertos:sha-bbc958b bash -c 'env | grep -E "FATFS|FREERTOS|MBEDTLS" | sort && ls /opt/fatfs/source/'
FATFS_PATH=/opt/fatfs
FREERTOS_KERNEL_PATH=/opt/freertos/kernel
FREERTOS_PLUS_TCP_PATH=/opt/freertos/plus-tcp
MBEDTLS_DIR=/opt/mbedtls
00history.txt 00readme.txt diskio.c diskio.h ff.c ff.h ffconf.h ffsystem.c ffunicode.c
```

`/opt/freertos/plus-fat` correctly absent. CI on this PR rebuilds the FreeRTOS host TDD and cross-build jobs against the new image SHA — that's the integration check.

Areas Affected

Devcontainer, CI workflow, BDD compose file, container reference docs, FreeRTOS adapter pack rationale comment. No production code touched.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores

  • Updated development and CI container images to latest versions for FreeRTOS build environments.
  • Updated build system documentation to clarify configuration approach.

• Documentation

  • Updated container reference documentation with current image details and contents.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR updates FreeRTOS container image references from SHA sha-10a14ae to sha-bbc958b across development and CI infrastructure, refines the CMakeLists documentation explaining INTERFACE library design, and updates public container documentation.

Changes

FreeRTOS Container Image Update

Layer / File(s)	Summary
Container image SHA updates across dev and CI infrastructure .devcontainer/docker-compose.yml, .github/workflows/ci.yml, ci/docker-compose.bdd.yml	FreeRTOS container image SHAs are updated to sha-bbc958b in devcontainer, GitHub Actions CI workflows, and BDD docker-compose configurations.
FreeRTOS CMakeLists design documentation Platform/FreeRtos/CMakeLists.txt	Clarified comments explain why the FreeRTOS adapter is an INTERFACE library due to header-configured data structures (TCBs, semaphores, SSL contexts) that vary with integrator configuration.
Container documentation updates docs/containers.md	Public documentation is updated with new image SHA and clarified descriptions for FreeRTOS host and cross-build images.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Possibly related PRs

• DavidCozens/solid-syslog#273: Previous PR that introduced the same FreeRTOS container infrastructure updates with CMakeLists documentation refinements.
• DavidCozens/solid-syslog#305: Related PR that modified FreeRTOS container image references across the same configuration files (devcontainer, CI workflows, BDD compose, documentation).

Poem

🐇 A rabbit hops through Docker SHAs,
New images for the FreeRTOS days!
From 10a14ae to bbc958b we go,
INTERFACE libraries steal the show,
Now documented for all to know! 📦

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title clearly and concisely summarizes the main change: bumping container image to a new SHA. It is specific, follows Conventional Commits format, and directly relates to the primary objective.
Description check	✅ Passed	The pull request description comprehensively covers all required template sections: Purpose (with issue link), Change Description (detailed file-by-file checklist), Test Evidence (pre-push verification output), and Areas Affected. Content is well-organized and substantive.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/bump-container-image-bbc958b

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[github-actions]

☀️   Quality Summary

   🚦   build-linux-gcc: 100% successful (✔️ 1112 passed, 🙈 3 skipped)
   🚦   build-freertos-host-tdd: 100% successful (✔️ 1199 passed, 🙈 3 skipped)
   🚦   build-linux-clang: 100% successful (✔️ 1064 passed, 🙈 3 skipped)
   🚦   sanitize-linux-gcc: 100% successful (✔️ 1064 passed, 🙈 3 skipped)
   🚦   integration-linux-openssl: 100% successful (✔️ 9 passed)
   🚦   integration-windows-openssl: 100% successful (✔️ 9 passed)
   🚦   bdd-linux-syslog-ng: 94% successful (✔️ 46 passed, 🙈 3 skipped)
   🚦   bdd-windows-otel: 90% successful (✔️ 44 passed, 🙈 5 skipped)
   🚦   bdd-freertos-qemu: 57% successful (✔️ 28 passed, 🙈 21 skipped)
   🚦   build-windows-msvc: 100% successful (✔️ 976 passed, 🙈 1 skipped)
   🚦   build-linux-tunable-override: 100% successful (✔️ 1064 passed, 🙈 3 skipped)
   ⚠️   Clang-Tidy: No warnings
   ⚠️   CPPCheck: No warnings

---

Created by Quality Monitor v1.14.0 (#f3859fd). More details are shown in the GitHub Checks Result.

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

docs/containers.md (1)

66-66: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Add ci/docker-compose.bdd.yml to the cpputest-freertos-cross update list.

The behave-freertos service in ci/docker-compose.bdd.yml (line 90) uses cpputest-freertos-cross, and this PR correctly updated it. However, the "Files to update" table doesn't list ci/docker-compose.bdd.yml for this image, which could cause that reference to be missed in future updates.

📝 Proposed fix

-| `cpputest-freertos-cross` | `.devcontainer/docker-compose.yml`, `.github/workflows/ci.yml`, `docs/containers.md` |
+| `cpputest-freertos-cross` | `.devcontainer/docker-compose.yml`, `.github/workflows/ci.yml`, `ci/docker-compose.bdd.yml`, `docs/containers.md` |

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@docs/containers.md` at line 66, Update the "Files to update" table row for
the entry `cpputest-freertos-cross` in docs/containers.md so it includes
`ci/docker-compose.bdd.yml` alongside the existing
`.devcontainer/docker-compose.yml`, `.github/workflows/ci.yml`, and
`docs/containers.md`; locate the table row containing the text
"`cpputest-freertos-cross` | `.devcontainer/docker-compose.yml`,
`.github/workflows/ci.yml`, `docs/containers.md`" and append `,
ci/docker-compose.bdd.yml` to that list.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@docs/containers.md`:
- Line 66: Update the "Files to update" table row for the entry
`cpputest-freertos-cross` in docs/containers.md so it includes
`ci/docker-compose.bdd.yml` alongside the existing
`.devcontainer/docker-compose.yml`, `.github/workflows/ci.yml`, and
`docs/containers.md`; locate the table row containing the text
"`cpputest-freertos-cross` | `.devcontainer/docker-compose.yml`,
`.github/workflows/ci.yml`, `docs/containers.md`" and append `,
ci/docker-compose.bdd.yml` to that list.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 94872516-b332-44c2-b6d9-9c171ebc432d

📥 Commits

Reviewing files that changed from the base of the PR and between 34f30ce and c2dd095.

📒 Files selected for processing (5)

• .devcontainer/docker-compose.yml
• .github/workflows/ci.yml
• Platform/FreeRtos/CMakeLists.txt
• ci/docker-compose.bdd.yml
• docs/containers.md