Move the portable example's pins, and record what the plan got wrong

[Sunrisepeak]

The specification does not change. No interface was added, none was altered, and
SURFACE.txt is untouched.

Two implementations do change: openkal-macos provides the five interfaces 0.8
added and openkal-windows provides four of them, so examples/portable — the
example that demonstrates one program above three implementations — names the
versions that have them.

§9 of the capability-completeness plan

.agents/docs/2026-08-27-capability-completeness-across-the-ecosystem.md gains
a section recording what was implemented, the four decisions §8 left open, and
five things the plan itself got wrong. Two are worth naming here:

⚠️ posix_spawn was never missing. openkal-musl replaced musl's source
when the port was written, and system and popen have worked through it ever
since. What was missing was a criterion.

⚠️⚠️ timeout_ns = 0 does not mean "do not wait" — it means no bound,
which timeout.h states and kal_task_wait established. The plan had it
backwards, and passing a caller's zero straight through turns the one call that
must not wait into the one that never returns.

And one thing nothing had noticed: no continuous integration anywhere selected
these interfaces. Every backend ran the conformance suite as full, which
expands to the hosted set, so every section for net, datagram, timeout,
exec and space was compiled with its body removed and reported as not
examined — in the same release that added them.

The four decisions, settled:

decision	outcome
fork() — trampoline or refusal	trampoline, and space.h asked for it in terms
permissions	refused, as recommended. Not an operation on the interface
symbolic links in 0.9	not now. The asymmetry stands recorded
openkal.space on Windows	declined permanently

---

This is one change across seven repositories, and every branch carries the
same name. Each repository's continuous integration substitutes its siblings'
working trees taken from the branch of the name under test, so the graph only
holds together when they agree.

repository	what it carries
openkal-musl	the socket, datagram, readiness and image-copying routes, and four probes
openkal-macos	the five interfaces 0.8 added
openkal-windows	four of the five; openkal.space declined in terms
openkal-linux	the conformance run selects the optional interfaces, which nothing did
openkal-llvm-runtime	__config_site's claims asserted by a program, and the C library repinned
openkal	the portable example's pins, and §9 of the plan
sbase	ninety-seven utilities above the new C library

The specification does not change. No interface was added, none was altered,
and SURFACE.txt is untouched — every capability below is composed from atoms
openkal 0.8 already had.