refactor: migrate EventStore and MessageStore to :outbox-api and :journal-api

- Replaced usages of `:message-store-api` and `:working-memory-api` with `:journal-api`, `:outbox-api`, and `:context-api`.
- Deprecated legacy `EventStore` and `MessageStore` interfaces, added `typealias` for backward compatibility.
- Updated imports across all modules with references to `:journal-api` and `:outbox-api`.
- Introduced `journalRoutes` and `outboxRoutes` in `:server` for audit log and live event stream endpoints.
- Adjusted `Agent` to expose read-only `journal` and `outbox` stores for improved modularity and clarity.
- Removed legacy Event and AgentEvent definitions from `:proto`, migrated to `:outbox-api`.
- Storage-related modules have been updated to support the new APIs consistently.

working-memory-api/build.gradle.kts

@@ -25,6 +25,7 @@ kotlin {
     sourceSets {
         commonMain.dependencies {
             api(project(":message-log-api"))
+            api(project(":context-api"))
             api(libs.kotlinx.coroutines.core)
             api(libs.kotlinx.serialization.core)
             api(libs.kotlinx.serialization.json)