feat: thread blocking_subscribe through PUT/GET operations

[iduartgomez]

Problem

When clients use subscribe=true on PUT/GET operations, subscriptions happen asynchronously. The blocking subscription infrastructure already exists (start_subscription_after_put() and start_subscription_request() both accept a blocking_subscription: bool), but the value was always hardcoded to false with TODO comments saying it should come from ContractRequest once stdlib was updated.

Solution

With freenet-stdlib 0.1.33 now providing blocking_subscribe: bool on ContractRequest::Put and ContractRequest::Get, this PR wires the field through the entire operation pipeline:

• put.rs: Added blocking_subscribe to PutState::PrepareRequest / AwaitingResponse, start_op() / start_op_with_id() signatures, and replaced all hardcoded false in start_subscription_after_put() calls (4 sites)
• get.rs: Added blocking_subscribe to GetState::PrepareRequest / AwaitingResponse, start_op() / start_op_with_id() signatures, and wired it through start_subscription_request() calls (2 sites, guarded by subscribe_requested && blocking_sub)
• client_events/mod.rs: Extracts blocking_subscribe from ContractRequest and threads it through all PUT/GET code paths (local-only, dedup router, legacy)
• request_router.rs: Added blocking_subscribe field to DeduplicatedRequest::Get and DeduplicatedRequest::Put
• Updated all call sites across core, fdev, and ping app with blocking_subscribe: false default

Backward compatible: the field defaults to false in both FlatBuffers and serde, so existing clients are unaffected.

Testing

• cargo fmt — clean
• cargo clippy --all-targets --all-features — no warnings
• cargo test -p freenet --lib — 1280 passed, 0 failed
• All request_router unit tests pass (18/18)

Dependencies

• Requires freenet-stdlib 0.1.33: feat: add blocking_subscribe field to PUT/GET contract requests freenet-stdlib#50