feat: Add originMetadata to requests

[FrederikBolding]

Add an originMetadata field to handlers arguments that also contain origin. This should only be used when the origin is using a non-verifiable transport.

https://consensyssoftware.atlassian.net/browse/WPC-1195

---

Note

Medium Risk
Touches the full inbound RPC path to Snaps and expands handler APIs; behavior is backward-compatible (optional field, null default) but Snaps may start relying on self-reported origin data for UX or policy.

Overview
Introduces OriginMetadata in snaps-sdk (transport, selfReportedOrigin) and threads optional originMetadata from multichain routing and SnapController through ExecutionService into the snap executor.

Snap handlers that already receive origin now also get originMetadata: OriginMetadata | null (defaults to null when omitted): onRpcRequest, onKeyringRequest, onProtocolRequest, and lifecycle hooks (onInstall, onUpdate, onStart, onActive, onInactive). JSDoc states this is for transports that cannot verify the origin.

SnapRpcHookArgs, snapRpc validation, and getHandlerArguments are updated accordingly; simulation/jest expectations include originMetadata: null when not provided. Browser tests cover passing metadata through multiple handler types.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.59%. Comparing base (a2ea600) to head (ff3d47c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4093   +/-   ##
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  Coverage   98.59%   98.59%           
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  Files         428      429    +1     
  Lines       12485    12495   +10     
  Branches     1975     1976    +1     
=======================================
+ Hits        12310    12320   +10     
  Misses        175      175           

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[GuillaumeRx]

Why do we get originMetadata on these ? 🤔

[FrederikBolding]

I was thinking in case we ever allow installation/update of Snaps on mobile, we would want to pass originMetadata there as well. Though we could remove this for now.

[GuillaumeRx]

I don't mind keeping it, that makes sense