feat(circuit-dsl): annotation-based circuit authoring API

[satran004]

Summary

Adds a Java annotation–based authoring style for ZK circuits on top of the existing CircuitSpec / SignalBuilder stack. Removes the duplicate declaration of input names (once in CircuitBuilder, once in define()), introduces typed symbolic values (ZkUInt, ZkBool, ZkField, ZkArray, ZkBits, ZkBytes), and generates *Circuit companion classes with typed build() / schema() / inputs() / circuitId() / metadata() / publicInputValues() surfaces.

Strictly additive — does not change CircuitSpec, CircuitBuilder, SignalBuilder, Signal, or ConstraintGraph. Generated code targets the existing builder API, so every existing example, test, and proving path continues to work unchanged.

ADR: docs/adr/circuit-annotation/README.md. Implementation broken into 9 phases with one commit per phase; phase docs live alongside the ADR.

What the new API looks like

Parametric Merkle membership (full equivalent of NWayMerkleCircuit):

@ZKCircuit(
        name = "membership-proof",
        nameTemplate = "membership-proof-d{depth}-{hashType}")
public class AnnotatedMerkleMembership {

    public AnnotatedMerkleMembership(@CircuitParam("depth") int depth,
                                     @CircuitParam("hashType") ZkMerkle.HashType hashType) { ... }

    @Prove
    ZkBool prove(ZkContext zk,
                 @Secret ZkField leaf,
                 @Public ZkField root,
                 @Secret @FixedSize(param = "depth") ZkArray<ZkField> siblings,
                 @Secret @FixedSize(param = "depth") ZkArray<ZkBool> pathBits) {
        return ZkMerkle.isMember(zk, leaf, root, siblings, pathBits, hashType);
    }
}

// Usage
var circuit  = AnnotatedMerkleMembershipCircuit.build(32, POSEIDON);
var schema   = AnnotatedMerkleMembershipCircuit.schema(32, POSEIDON);
var witness  = AnnotatedMerkleMembershipCircuit
        .inputs(32, POSEIDON) 
        .leaf(leafValue)
        .root(rootValue)
        .sibling(0, ...) ... .pathBit(0, ...) ...
        .toWitnessMap();

Range proof (field-style, the simplest case):

@ZKCircuit(name = "range-proof")
public class RangeProof {
    @Secret @UInt(bits = 64) ZkUInt secret;
    @Public @UInt(bits = 64) ZkUInt lo;
    @Public @UInt(bits = 64) ZkUInt hi;

    @Prove
    ZkBool inRange() {
        return secret.gte(lo).and(secret.lte(hi));
    }
}

New modules

• zeroj-circuit-annotation-api — annotations, symbolic Zk* types, ZkContext,
  ZkCircuitSchema, ZkCircuitMetadata. Depends only on zeroj-circuit-dsl.
• zeroj-circuit-annotation-processor — javac annotation processor that emits
  *Circuit companion classes. Registered via META-INF/services/javax.annotation.processing.Processor.

Symbolic gadget adapters live in zeroj-circuit-lib under com.bloxbean.cardano.zeroj.circuit.lib.zk.* so the annotation API stays independent of optional gadgets:

• ZkMiMC, ZkPoseidon, ZkMerkle (Phase 3 — first usable slice)
• ZkPedersen, ZkJubjubPoint, ZkEdDSAJubjub (Phase 8)

All adapters are thin wrappers over existing Signal* gadgets with
differential tests.

Both new modules are included in zeroj-bom-core and zeroj-bom-all.