New crate defining the host syscall traits (storage, navigation, consent,
permissions, ...) that host runtimes implement. Types are re-exported from
truapi::versioned/v01 rather than redefined.

WASM host runtime that hosts implement: dispatcher, SCALE frames, subscription
streams, chain runtime, host logic (sessions, SSO pairing, permissions,
statement store, dotns) and the wasm bindings. Includes the committed generated
dispatcher/wire-table under src/generated/.

…backs

Extends the rustdoc-JSON code generator to emit the Rust dispatcher and wire
table consumed by truapi-server, plus the TS host-callbacks adapter. Golden
tests pin the emitted shapes.

New WASM-backed host runtime package embedding the Rust core, with web iframe
and Web Worker entry points. Updates the @parity/truapi client (SCALE, sandbox,
transport) and drops the obsolete explorer 0.3.2 codegen snapshot.

Updates CLAUDE.md/README, CI workflows, Makefile, deny.toml, changesets, and
linguist attributes for generated code, and bumps the dotli submodule to the
host integration that consumes the WASM runtime.

Adds the canonical testing module (api/testing.rs) and its v01/v02/versioned
wiring used by the Rust host runtime and generated clients.

New crate defining the host syscall traits (storage, navigation, consent,
permissions, ...) that host runtimes implement. Types are re-exported from
truapi::versioned/v01 rather than redefined.

…backs

Extends the rustdoc-JSON code generator to emit the Rust dispatcher and wire
table consumed by truapi-server, plus the TS host-callbacks adapter. Golden
tests pin the emitted shapes.

…st callbacks

…st callbacks

…st callbacks

…st callbacks

…st callbacks

Move the entire Bulletin TransactionStorage.store submission into
truapi-server. The core builds the extrinsic offline (subxt 0.50.2), signs
it with the wallet-delegated allowance key, dry-runs it, broadcasts, and
watches for inclusion over the existing chainHead runtime — replacing the
host signer-callback seam so the allowance secret never crosses the
host/FFI boundary.

Core:
- host_logic/extrinsic.rs: offline SubstrateConfig assembler with a
  config-pinned genesis hash, an sr25519 Signer, and metadata / transaction
  validity / events / header decoders.
- host_logic/bulletin.rs: store{data} construction signed with the allowance
  key, with audited pallet/call-index pinning plus a canonical-bytes guard so
  provider metadata cannot redirect the signature, and a memcpy call-data
  encoder that avoids scale-encode's per-byte cost.
- runtime/bulletin_rpc.rs: serialized submit flow (ephemeral with_runtime
  follow, metadata, nonce, validate_transaction dry-run, broadcast, single
  event-loop inclusion watch gated on nonce advance, System.Events dispatch
  check), typed error taxonomy, and broadcast stop on every exit.
- runtime.rs: Preimage::submit gates on bulletin availability before any
  prompt and refreshes the allowance (Increase policy) with one retry on an
  allowance rejection; lookup_subscribe verifies blake2_256(value)==key and
  serves an in-core content-addressed cache.
- BulletinAllowanceKey is zeroized on drop; PreimageHost keeps only
  lookup_preimage; both host configs gain an optional Bulletin genesis hash.

Codegen/TS: regenerate goldens (product wire unchanged) and drop the signer
bridge from the handwritten host worker. CI compiles the crate for
wasm32-unknown-unknown; .gitignore ignores the renamed wasm bundle path.

Bumps the hosts/dotli gitlink to the matching submodule commit.

Adversarial review of the watch loop found two defects:

- A crafted or buggy chain provider could send a self-referential or cyclic
  `NewBlock` parent link. The nonce-advance ancestor walk had no visited-set
  guard and no `.await`, so such a link spun forever, freezing the worker and
  permanently holding the submit lock across all products. The walk is
  extracted into `ancestors_to_check`, which guards against self-parent and
  cyclic links with a visited set, and is unit-tested.
- Blocks that failed the nonce gate were marked checked but never unpinned,
  leaking chainHead pins over the watch's lifetime and risking a false
  BroadcastUnverified once the server's pin limit was hit. They are now
  unpinned like body-negative blocks.

Also log a warning when a host lookup value is downgraded to a miss for
failing the blake2_256(value)==key integrity check.

…bler

The signing-host role now builds and signs transactions locally instead of
returning Unavailable, reusing host_logic/extrinsic.rs.

Because ProductAccountTxPayload carries each extension's `extra` and
`additional_signed` already SCALE-encoded in canonical order, assembly is a
pure offline concatenation — no metadata, no RPC:

- extrinsic.rs gains build_signed_extrinsic_v4 + v4_signer_payload and an
  Sr25519Signer::from_keypair constructor. Body = Compact(len) ++ 0x84 ++
  MultiAddress::Id(signer) ++ MultiSignature::Sr25519(sig) ++ Σextra ++
  call_data; signer payload = call_data ++ Σextra ++ Σadditional_signed,
  blake2_256 only when >256 bytes. Layout is byte-identical to subxt /
  frame-decode.
- signing_host::create_transaction handles Product and LegacyAccount (with a
  fail-closed slot-zero key-match check); the product-facing entrypoint's
  caller-scoping, chain-submit permission, and user-confirmation gates already
  precede it.
- Extrinsic V5 (tx_ext_version != 0) returns the new AuthorityError::NotSupported
  -> HostCreateTransactionError::NotSupported: V5 general carries the signature
  inside a VerifySignature extension, which cannot come from pre-encoded parts.

Tested: v4 layout + signature verification, the >256 hashing boundary, extension
order preservation, and Product/LegacyAccount success plus v5/mismatch/no-session
rejections.

Keep physical provider ownership in hosts while moving shared chain behavior and Subxt-backed handling into Rust. Harden Bulletin retries and host lifecycle coverage.