fix(client,doc): address review — flow-open busy gating, seam on the architecture map, browse gap documented

- While a picking flow is open (native chooser pending, browse dialog up) or
  its pick is being adopted, every other menu action disables: a late outcome
  must not race a concurrent selection or creation (ds-review-bot warning).
- ctx.directoryPicker joins the architecture Capability Services map (both
  languages); neighboring rows condensed to keep the doc inside its ceiling.
- directory-picker-browse documents that its client half lands in the next
  stacked PR: a -browse composition today hides the picking affordance (the
  documented empty-hole default) rather than misbehaving (ds-review-bot
  critical; the dialog itself ships in #821).

docs/architecture.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write docs/architecture.md
-architecture.md: 054985ac5ea32a44b9daca3c1abfd58dcdc5d897
-architecture.zh.md: 84876faf2ae27069ba8bd026bcfbc56e32f65574
+architecture.md: 2ae982eba49b6dbd2365496915f9917071167813
+architecture.zh.md: abaef961504ff64dbcd1e8e8ba9bd002406fa7f4