Rebrand alknet-typedef to alktype in docs, crate name, and lib name

Renumber ADRs 095-102 to 001-008 and OQs 069-071 to 001-003, and
update all cross-references (titles, body prose, file-path links,
tables) across the 5 spec docs, README, open-questions index, and
all 11 ADR/OQ files. Inline the ADR-009 door-type definition from
the parent alknet project (broken cross-project reference).

Rebrand prose: alknet-typedef -> alktype in headings, body text,
dependency diagrams, and "additions" notes. Disambiguate the prior
failed attempt at /workspace/@alkimiadev/alktype/ as "the
@alkimiadev/alktype prototype" to distinguish it from this crate.
Historical research citations (docs/research/*, /workspace/alknet-typedef-poc/)
are kept as-is for provenance.

Rename the crate in Cargo.toml ([package].name, [lib].name) and
update the 11 use alknet_typedef::* imports across the 4 test files.
Rebrand the crate-level doc comment in src/lib.rs.

The TypeDef:* keyword strings, TypedefError/TypedefEngine identifiers,
and other code-level references are unchanged — those are a separate
code rebrand pass.

Build, 295 tests, and clippy all pass clean.

tests/poc_roundtrip.rs

@@ -8,9 +8,9 @@
 //! reads them back, asserting both the values and (where applicable)
 //! the byte positions.
 
-use alknet_typedef::data_access;
-use alknet_typedef::tunion;
-use alknet_typedef::*;
+use alktype::data_access;
+use alktype::tunion;
+use alktype::*;
 use serde_json::json;
 use std::collections::HashMap;