feat!: winscard: remove scars cache seed and make it global

[Pavlo Myroniuk (TheBestTvarynka)]

Hi,

I fixed the scard logon for system-provided smart cards in this PR. Overall, this PR introduces two major changes:

1. The scard cache is global now. It means that we have one cache for all contexts and scard handles. The previous approach with cache per context was incorrect.
2. The scard cache seed was removed to the system-provided smart card (but still present for emulated smart cards). It was a small shock for me when I found out that the scard logon can work well without a seeded cache.

[Copilot]

Copilot review overview

🟡 Changes recommended

Cache entries are not isolated by card identifier, initialization can overwrite shared state, and raw cache payloads are logged.

Review effort: Balanced
Findings: 2 · 1

Open (3)

• Include card UUID in cache keys to isolate card entries · New
• Avoid logging complete opaque cache payloads · New
• Install cache seeds atomically to prevent global partial state · New

What changed in this PR

Makes smart-card caching process-global while removing cache seeding for system-provided cards.

Changes:

• Adds a synchronized global cache with freshness handling.
• Injects the cache into emulated contexts.
• Simplifies system-card context initialization.

File	Description
ffi/​src/​winscard/​system_scard/​context.rs	Uses the global cache on non-Windows systems.
ffi/​src/​winscard/​scard_context.rs	Injects the global cache and adds write diagnostics.
ffi/​src/​winscard/​piv.rs	Updates system-context construction.
ffi/​src/​winscard/​mod.rs	Registers the cache module.
ffi/​src/​winscard/​cache.rs	Implements global cache storage and tests.
crates/​winscard/​src/​scard_context.rs	Accepts a cache implementation and seeds it.
crates/​winscard/​src/​lib.rs	Exports the cache abstraction.
crates/​winscard/​src/​cache.rs	Defines the public cache trait.

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[Pavlo Myroniuk (TheBestTvarynka)]

First, I decided to support only one smart card per system. But then I found out that I needed to support multiple smart cards. It turned out it wasn't as hard as I thought. Done in ffaf9ba

Now we support multiple system-provided smart cards.
Pay attention: we still support only one smart card per system for emulated smart cards.

[Pavlo Myroniuk (TheBestTvarynka)]

Benoît Cortier (@CBenoit), I addressed Copilot's comments and resolved merge conflicts