starkernel: land console_fb_init() reorder (FABRIC.md 4.4g decided)

Moves the console_fb_init() call in kernel_main.c from after
capsule_birth_mama() to before it, so the fleet-birth/self-test
transcript (Hermes x2, Artemis births, Stadium self-tests -- currently
serial-only) is also framebuffer-visible, not just the small post-birth
tail.

4.5f's -O2 experiment already showed this doesn't hang under
optimization, just costs roughly 12x more boot-time heartbeat ticks
(one-shot, paid only during fleet birth, never repeated at runtime).
Captain Bob's call: worth it, since the serial log was never the
problem -- this is about the same transcript also reaching a real
screen.

Three-arch verified: amd64/aarch64/riscv64 all reach ok>, POST
Failed: 0, identical dict-hashes across all three. amd64 screendump
confirms the framebuffer now carries the full transcript.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

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