Refactor/journey pilot - #3

Complete beat 00-08 + epilogues A/B under the new paradigm: experiment +
verify script run green locally first, chapter written against the real
transcript, prose polished to the content_forge target voice.

- 00 env check (script doubles as the beat's teaching artifact)
- 01 gcc pipeline + ELF dissection (nm/readelf/objdump; gcc's printf->puts)
- 02 gdb (break/bt/watch, -O2 optimized-out, UB warning as evidence)
- 03 make (undefined-reference incident -> dependency accounting)
- 04 cmake (lib/app split, compile_commands.json, incremental semantics)
- 05 cross-compile (dumpmachine, rdimon semihosting, arch diff, objcopy)
- 06 bare-metal UART on qemu mps2-an385: vector table + linker script,
  volatile MMIO driver, expected-serial.txt committed as real capture
  (268-byte image), remote gdb via qemu gdbstub closes beat-02 foreshadow
- 07 git deep-dive (restore, branch, real merge conflict, tag) + README
- 08 vscode wiring (settings/launch/tasks; tier manual, JSON checks scripted)
- 90/91 physical serial + lab safety epilogues (tier manual)
- scripts/: run-all hub + command-consistency lint (94 commands, 0 warn);
  manual-tier chapters exempted from script pairing
- CI: verify job on ubuntu+windows matrix (git-bash), lint in warn mode
- site home rerouted to journey as the recommended entry