S24.05: Move BDD-target binaries from Example/ to Bdd/Targets/<platform>/

[DavidCozens]

Parent epic: #254 (E24: Code Hygiene)

Depends on: #332 (S24.04 must land first — this is a pure rename
sweep over what remains)

Overview

After S24.04 leaves one binary per platform (Example/Threaded on
Linux, Example/Windows, Example/FreeRtos/SingleTask), all three
are BDD test infrastructure rather than pedagogical examples. They
live under Example/ for historical reasons and the directory name
Example/FreeRtos/SingleTask/ actively misdescribes its contents
(buffered, two SolidSyslog-touching tasks post-S08.04 slice 2).

Move them under Bdd/ alongside the features and step definitions so
the role is structurally obvious. Frees Example/ for the future
SL1 / SL2 / SL3 pedagogical examples (separate epic, not in scope
here).

Why

• "Example" misnames test infrastructure.
• Example/FreeRtos/SingleTask/ directory name is wrong post-S08.04
  slice 2 — it's not single-task any more.
• Pre-launch (v0.0.0); no external readers to consider.
• Example/ directory becomes free for genuine pedagogical examples
  later.

In scope

• Example/Threaded/ → Bdd/Targets/Linux/
• Example/Windows/ → Bdd/Targets/Windows/
• Example/FreeRtos/SingleTask/ → Bdd/Targets/FreeRtos/
• Example/Common/ and Example/FreeRtos/Common/ — likely move too
  (they're consumed only by the moved targets), to Bdd/Targets/Common/
  and Bdd/Targets/FreeRtos/Common/ respectively. Decide as part of
  the slice; if a future SL1 example will reuse ExampleInteractive
  etc., a Bdd/Targets/Shared/ may be the right destination instead.
• CMake target renames as appropriate. Suggested mapping:
  • SolidSyslogThreadedExample → SolidSyslogBddTargetLinux
  • SolidSyslogExample (Windows .exe) → SolidSyslogBddTargetWindows.exe
  • SolidSyslogFreeRtosSingleTask (.elf) → SolidSyslogBddTargetFreeRtos.elf
    Names are bikeshed-negotiable; pick at implementation time.
• Bdd/features/environment.py default example_binary paths
  updated to the new locations.
• .github/workflows/ci.yml ELF artefact upload / download paths for
  build-freertos-target → bdd-freertos-qemu, and any equivalent
  Windows artefact movements.
• Tests/Example/ directory (host-side unit tests of shared helpers
  like ExampleInteractive, ExampleCommandLine, ExampleAppName,
  …) — move under Tests/Bdd/Targets/ or similar, tracking wherever
  the Common/ directory landed.
• README's "Four example programs" pitch updated to reflect the new
  shape (one buffered BDD target per platform under Bdd/Targets/).
• docs/iec62443.md, docs/bdd.md, Bdd/README.md,
  Example/FreeRtos/README.md (if it still exists post-rename) —
  update path references.
• Bdd/features/steps/syslog_steps.py — drop the THREADED_BINARY
  constant; collapse run_buffered_example routing if S24.04 didn't
  already.

Acceptance criteria

• Example/ no longer contains any platform-specific subdir
  (only Common/ if it stays — or nothing).
• Bdd/Targets/Linux/, Bdd/Targets/Windows/, and
  Bdd/Targets/FreeRtos/ exist with the moved sources.
• bdd-linux-syslog-ng, bdd-windows-otel, and
  bdd-freertos-qemu all green on CI.
• build-freertos-target / build-windows-msvc / build-linux-gcc
  / build-linux-clang all green.
• analyze-format, analyze-tidy, analyze-cppcheck all green
  (no broken include paths from the rename).
• No references to the old Example/<platform>/ paths remain in
  CMakeLists, CI workflow, BDD harness, or docs.

Out of scope

• Functional changes to the binaries themselves — pure rename.
• New SL1 / SL2 / SL3 examples.

Risks

• The --app-name "SolidSyslogThreadedExample" pin in
  Bdd/features/steps/syslog_steps.py::build_threaded_command keeps
  Linux/Windows wire record sizes byte-equal so
  store_capacity.feature's records-per-block math works. After the
  rename, either keep the pin against the new basename or re-audit
  the capacity numbers. Pin-keep is the safer default.
• CI artefact paths (SolidSyslogFreeRtosSingleTask.elf, etc.) are
  referenced in workflow jobs that depend on each other across the
  bdd-freertos-qemu ↔ build-freertos-target boundary; rename in
  lock-step.
• Devcontainer launch configurations (Debug FreeRTOS (QEMU)) and
  VS Code task definitions may hard-code the binary path — sweep
  .vscode/ / .devcontainer/ too.

References

• E24 E24: Code Hygiene #254 charter.
• S24.04 (S24.04: Migrate Linux BDD off Example/SingleTask; remove the SingleTask binary #332) — prerequisite that takes the Linux binary count from
  two to one.
• Conversation 2026-05-11 in PR feat: S08.04 SolidSyslogFreeRtosMutex + buffered FreeRTOS example #330 close-out turn — captured in
  agent memory project_example_consolidation_plan.