Clean up rebranding drift in docs, agent configs, and source comments

Fix stale references left over from the alknet-typedef → alktype migration:
- .opencode/agents/: replace @alkdev/alknet constraints (tokio, crypto, feature
  flags, anyhow/thiserror) with alktype-accurate ones (sync, AlkTypeError,
  WASM-clean); fix @alkimiadev → @alkdev org name; remove nonexistent AGENTS.md
  ref; replace alknet-http/alknet-agent spec examples
- docs/sdd_process.md: fix wrong package name (@alkdev/storage → @alkdev/alktype)
- docs/architecture/: rewrite dangling /workspace/ and docs/research/ paths as
  @alkdev/alknet: cross-repo references with explanatory notes; fix
  @alkimiadev → @alkdev; fix 'not yet used by any alknet crate' stale context
- src/ + tests/: correct '17 AlkType kinds' → '19' in doc comments (enum has 19
  variants; pre-existing count error); fix dangling /workspace/ path in
  poc_roundtrip.rs

docs/architecture/questions/001-arrays-of-variable-length-element-structs.md

@@ -2,8 +2,8 @@
 
 - **Origin**: [../layout-engine.md](../layout-engine.md),
   [../data-access.md](../data-access.md);
-  `docs/research/alknet-typedef/findings.md` §"Problem 3: Nested structs
-  and arrays of structs"
+  `@alkdev/alknet: docs/research/alknet-typedef/findings.md` §"Problem 3:
+  Nested structs and arrays of structs"
 - **Status**: deferred(scope)
 - **Door type**: Two-way (additive — the engine can add lazy walking
   logic without changing the existing fixed-stride array support)

docs/architecture/questions/002-no-std-alloc-support.md

@@ -1,7 +1,8 @@
 # OQ-002: `no_std` + `alloc` support
 
 - **Origin**: [../overview.md](../overview.md);
-  `docs/research/alknet-typedef/findings.md` §"Open Questions" (OQ 6)
+  `@alkdev/alknet: docs/research/alknet-typedef/findings.md` §"Open
+  Questions" (OQ 6)
 - **Status**: deferred(scope)
 - **Door type**: Two-way (additive — can be added as a feature gate
   without changing the existing `std` API)

docs/architecture/questions/003-builder-api-for-schema-construction.md

@@ -2,8 +2,8 @@
 
 - **Origin**: [../schema-layer.md](../schema-layer.md),
   [../overview.md](../overview.md);
-  `docs/research/alknet-typedef/findings.md` (the builder API was noted
-  as the one detail not covered by the POCs)
+  `@alkdev/alknet: docs/research/alknet-typedef/findings.md` (the builder
+  API was noted as the one detail not covered by the POCs)
 - **Status**: deferred(scope)
 - **Door type**: Two-way (additive — a builder API can be added without
   changing the existing JSON-consumption path)