fix: resolve all post-merge compile errors

- Fix unresolved imports (auto_compaction, AutoCompactionEvent)
- Add Thinking/RedactedThinking match arms
- Fix workspace.dependencies serde_json
- Fix enum exhaustiveness in OutputContentBlock matches
- cargo check --workspace passes

rust/crates/runtime/src/lib.rs

@@ -31,8 +31,8 @@ pub use config::{
     RuntimePluginConfig, ScopedMcpServerConfig, CLAW_SETTINGS_SCHEMA_NAME,
 };
 pub use conversation::{
-    auto_compaction_threshold_from_env, ApiClient, ApiRequest, AssistantEvent, AutoCompactionEvent,
-    ConversationRuntime, RuntimeError, StaticToolExecutor, ToolError, ToolExecutor, TurnSummary,
+    ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, StaticToolExecutor,
+    ToolError, ToolExecutor, TurnSummary,
 };
 pub use file_ops::{
     edit_file, glob_search, grep_search, read_file, write_file, EditFileOutput, GlobSearchOutput,