feat(type-provider): add FScript export type provider with strict runtime signature checks

[pchalamet]

Summary

Adds a new MagnusOpera.FScript.TypeProvider package that projects [<export>] FScript functions into strongly-typed F# static methods.

The provider:

• parses and type-checks scripts at compile time,
• fails F# compilation on script parse/type errors,
• exposes exported functions with mapped argument/return types,
• supports runtime script replacement through a provider-level resolver,
• enforces strict runtime signature compatibility via compile-time fingerprint checks.

Main changes

• New project: src/FScript.TypeProvider
  • Provider.fs (type provider entry + generated members)
  • Contract.fs (type mapping, fingerprinting, serialized contract)
  • ScriptRuntime.fs (extern resolution, runtime loading, invocation, compatibility checks)
• Runtime extraction helper: src/FScript.Runtime/ExportSignatures.fs
  • ScriptHost now reuses this shared exported-signature extraction path.
• Solution wiring:
  • added FScript.TypeProvider and FScript.TypeProvider.Tests to FScript.sln.

Supported exported signature shapes (v1)

• unit, int (int64), float, bool, string
• list<T>, option<T>, tuples (2..8), map<string, T>

Unsupported exported types fail provider generation (records/unions/named types/function values/unresolved generics/non-string map keys).

Tests

Added integration coverage in tests/FScript.TypeProvider.Tests with fixture projects:

• valid script compiles and exposes callable members,
• compile fails on script type errors,
• compile fails on unsupported exported signature shapes,
• runtime override succeeds with compatible signatures and fails on signature mismatch.

Docs + release notes

• Added spec: docs/specs/fsharp-type-provider.md
• Updated:
  • docs/specs/README.md
  • docs/specs/embedding-fscript-language.md
  • docs/architecture/assemblies-and-roles.md
• Updated CHANGELOG.md ([Unreleased]).

Validation

• make build
• make test
• make smoke-tests