Fix: three Phase 10 defects and correct the Phase 10 documents - #59

…install

A three-pass review (shape, adversarial, reader) over 27fb81f. The shape
held: the guarded installs are NFR-10's repair, not a workaround, and the
Node floor stays >=20.3. Reading the running code rather than the diff
turned up three more live defects, all on the same seam.

- scripts/verify-dual-consumption.mjs asserted
  `typeof transport[Symbol.asyncDispose] === 'function'` unguarded, inside a
  blocking CI gate. On the >=20.3 floor that reads transport['undefined'] —
  which, before 27fb81f, resolved to the junk prototype entry the bug itself
  created. The gate's greenness depended on the defect it existed to catch;
  fixing the defect broke the gate, and CI could not see it because the `ci`
  job runs setup-bun's default node. Reproduced on real Node 20.3.0:

      AssertionError: 'undefined' !== 'function'   (exit 1)

  Now guarded, and asserts the junk key's absence on both legs.

- UndiciTransport.close() walked `owned` with a bare `for … await`, so the
  first rejecting destroy() abandoned the rest. The set is walked reversed,
  so with a proxy configured the leaked dispatcher is the ProxyAgent holding
  the pooled connections — a teardown path that leaked exactly what it was
  called to release. The raw undici error also escaped a public method
  untyped. Every dispatcher is now destroyed before anything throws, and
  failures surface as TransportFailureError with {cause}, AggregateError
  when several fail. close() memoizes the rejection, so TRANSPORT-16's
  "stable state" holds: the same error object comes back every time.

- UndiciTransport.send() called prepareBody() before toUndiciHeaders(), and
  header mapping reads request.body.mediaType — a getter on a caller-supplied
  Body that can throw. pumpBody starts its producer eagerly, so the throw
  escaped with a live producer nothing could abandon and a rejection headed
  for Node's default unhandledRejection policy: the SEAM-30 hazard
  body-pump.ts documents. Header mapping is hoisted above body preparation.
  FetchTransport was already correct by object-literal evaluation order, which
  is implicit and easy to regress, so it gets the same guard test.

- The undici disposal test asserted only that the member existed; an
  asyncDispose wired to a bare resolved promise passed it. It now swaps
  undici's Agent binding for a capturing subclass and asserts the owned
  dispatcher is destroyed by dispose alone.

Closes the sideEffects question 27fb81f opened. Four packages now carry a
module-scope Object.defineProperty install while declaring "sideEffects":
false. packages/shrink-test/ asserts the symbol survives a real esbuild
bundle + minify + treeShaking pass, negative-tested by stripping the install
from the built page.js. sideEffects was deliberately not narrowed to four
paths — a narrow list goes stale on the next file move and fails open.
Widens the NFR-12 gate to the leg 27fb81f verified by hand. npm pack is
deterministic here (npm normalizes tar entries rather than stamping wall-clock
time), so all 9 publishable packages are packed and digest-compared on both
clean builds. Injecting Date.now() into gen-version.mjs now fails both legs,
naming dist/generated/version.js and npm-pack:dexpace-core-0.0.0.tgz. The
gate's registration was also one place short: ci-preflight's SKILL.md
playbook table had no row for it, and five step counts across that skill were
stale.

Makes the doc tree describe what Phase 10 became:

  roadmap :65, design :15   asserted "review only" / "ships no package".
                            It shipped a breaking type change across three
                            packages, two changesets, a blocking CI step, and
                            four defect fixes — the same assert-without-
                            checking this phase spent 86 lines correcting
  §10 ↔ docs/deviations.md  two ledgers on one numbering scheme with no
                            cross-reference, and a third file with a nearly
                            identical name. All three now disambiguated
  knowledge corpus          deliberate-deviations.md pins sha f9ecb6e7d87b,
                            traced to 05d649a — three revisions back. Flagged
                            at the head, and inline on the two entries that
                            are substantively false, so the correction reaches
                            `bun run knowledge` output and not just a reader
  roadmap :169              maxRetries was already fixed in cba4721; the row
                            claiming Phase 10 owned it is marked resolved
  F2, F7, CONSTANT_CASE     project-wide convention sweeps, recorded Not
                            scheduled with triggers. Phase 10 is the last
                            roadmap row, so there was no honest owner to name

Records the floor decision where it will be found. Raising engines.node to
>=20.4 to restore `implements AsyncDisposable` was recorded as a pending
unblock; it is now decided against, in open-items.md and the two other places
the recommendation had spread to. NFR-10 requires a higher-floor capability to
be isolated into its own unit rather than lifting the general-purpose core's
floor, and requires the emitted target and visible-API level to agree — the
clause the unguarded member violated. >=20.3 is derived, not chosen: the
lowest Node that runs what these packages emit, set by globalThis.crypto
(absent from ESM on every Node 18) and AbortSignal.any() (20.3.0). Phase 4b
already decided this shape once, shipping a guarded suppress() rather than
moving the floor for SuppressedError.

Verified: preflight 15/15 --clean and 16/16 --node-floor on the pinned Bun
1.3.14, including the real Node 20.3.0 leg; 2175 tests.