Add InstallIdProvider (UUID v7 + SharedPreferences) and bump to 0.0.4

[JakubMrozek]

Summary

• New deviceinfo/InstallIdProvider.kt: a public object exposing getOrCreate(context): String, which returns a UUID v7 per-app-install identifier persisted in a dedicated kontextso SharedPreferences file under the installId key. Generated on first call, survives launches, resets only on uninstall / app-data clear.
• Bumps kit = "0.0.3" → "0.0.4" and adds a 0.0.4 CHANGELOG.md entry.

Mirrors kontextkit-ios's InstallIdProvider (which reads/writes UserDefaults.standard) and the kontextso:installId localStorage key used by @kontextso/sdk-js, so web, iOS, and Android installs share the same shape on the wire.

Why now

sdk-kotlin is wiring installId into its /init, /preload, /error, and /debug request payloads as part of the v4 release (see sdk-kotlin PR #103). Threading the field on the consumer side is blocked on this kit ship — sdk-kotlin will pin to 0.0.4 once it's on Maven Central.

Design notes

• UUID v7 (RFC 9562 §5.7): 48-bit big-endian Unix-epoch ms in bytes 0–5; version 0111 in byte 6; variant 10 in byte 8; remaining bits from SecureRandom. Time-ordered, so server-side sorts and B-tree indexes stay friendly.
• Validator is version-agnostic: checks the canonical 8-4-4-4-12 hex shape only, not v7-specific bits. A future generator change (e.g., v8) won't invalidate IDs already on users' devices.
• Strict shape check via regex — java.util.UUID.fromString accepts shorthand like "1-2-3-4-5", which would round-trip forever once stored.
• Storage location: dedicated kontextso SharedPreferences file, not the host app's default prefs. Keeps the install ID out of any file the IAB TCF library reads/writes through PreferenceManager.getDefaultSharedPreferences, and gives the host app a single file name to clear if they ever need to reset the ID.

Test plan

• ./gradlew spotlessCheck detekt test — BUILD SUCCESSFUL locally
• 15 unit tests in InstallIdProviderTest.kt:
  • v7 shape match (canonical regex)
  • Timestamp prefix is within before..after system millis
  • Time-ordering across distinct millisecond boundaries
  • getOrCreate generates and persists on first call
  • getOrCreate returns same value on subsequent calls
  • Pre-seeded value is returned untouched
  • Forward-compat: a stored v4 UUID is accepted (version-agnostic validator)
  • 6 malformed-input overwrite cases (empty / non-UUID / truncated / extras / JSON / non-hex)
  • Android-specific: "1-2-3-4-5" shorthand is rejected (would pass UUID.fromString)
  • Direct isCanonicalUuid accept/reject sanity

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