docs(#2346): Command Dispatch Completion ADR + graduate ADR-959 to Accepted (#2355)

Records the decision (ADR-2346) to dissolve runCommand's 73-case switch into a
two-layer dispatch (registry families + leaf-verb table filling the prepared
_dispatchNonFamily seam), collapsing it to ~15 lines. Covers the four decisions
ADR-959 leaves open: full dissolution, family/leaf classification rule, shared
parseFamilyArgs, and the capability-arm extraction shape. Phased under epic
#2345 (P1-P4). Behavior-preserving; each cutover proven by the
audit-command-cutover equivalence template.

- docs/adr/2346-command-dispatch-completion.md (new)
- docs/adr/959-*.md: Status Proposed -> Accepted + amendment section
- docs/adr/README.md: index rows for 959 + 2346
- docs/ARCHITECTURE.md: forward-reference note under Command Routing Hub
- CONTEXT.md: seed glossary entry

Closes #2346 (docs-only; no production code).

docs/ARCHITECTURE.md

@@ -305,6 +305,8 @@ See [`docs/INVENTORY.md`](INVENTORY.md#hooks) for the authoritative hook roster.
 
 CJS command family routers dispatch through `CommandRoutingHub`. The hub owns the no-throw pure-result contract (`hub.dispatch()` catches internal exceptions and returns `{ ok: false, kind, ...typedPayload }`) and the closed runtime error taxonomy (`UnknownCommand`, `InvalidArgs`, `HandlerRefusal`, `HandlerFailure`). Router adapters remain thin CLI translators — they build the hub, call `dispatch`, then map the Result to `output()`/`error()` calls. The runtime is single-path (no dual-runtime mode selection). See `docs/adr/0174-retire-gsd-sdk-package-boundary.md`.
 
+> **Planned (ADR-2346 / epic #2345):** the `runCommand` 73-case switch is being dissolved into a two-layer dispatch — families via the `commandFamilies` registry (ADR-959 mechanism, completed) and single-purpose leaf verbs via a table filling the prepared `_dispatchNonFamily` seam — collapsing `runCommand` to a ~15-line dispatcher. Behavior-preserving; tracked phase-by-phase under epic #2345. The current-state description above holds until each phase lands.
+
 ### Capability Command Dispatch (`gsd-core/bin/gsd-tools.cjs`, ADR-1244 D7)
 
 Command families declared by capabilities (`commands: [{ family, module, router }]`) are dispatched from the registry rather than a hardcoded switch. The `runCommand` default arm tries, in order: