feat: Claude Code CLI v2.1.105–v2.1.131 support (#274)

## Overview

Full audit and implementation of Claude Code CLI changelog entries from v2.1.105 through v2.1.131.

## Changes

### Implemented

- **#268** — Add `claude-opus-4-7` to the model picker, update all model pricing and context window sizes (also fixes a bug where `claude-opus-4-6` was coded as 200K context instead of 1M)
- **#269** — Expose effort level setting in UI via `--effort <level>` flag (`low`, `medium`, `high`, `xhigh`, `max`)
- **#273** — Expose prompt caching TTL env vars in UI (`ENABLE_PROMPT_CACHING_1H` / `FORCE_PROMPT_CACHING_5M`)
- **#267** — Add `PreCompact` hook support — emits `claude:pre-compact` event with "Compacting context..." toast and thinking state
- **#270** — Parse `plugin_errors` from stream-json init event and surface them as error output lines
- **#266** — Bump supported CLI version constant to `2.1.131`

### Closed as Not Applicable

- **#271** (`autoScrollEnabled`) — TUI-only setting; we manage our own scroll behaviour
- **#272** (`tui` fullscreen mode) — TUI-only setting; we use stream-json and never activate the TUI

## Testing

All checks pass (`./check-all.sh`) including frontend lint, format, type check, Vitest coverage, Clippy, and Rust test coverage.

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #274
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src-tauri/src/types.rs

@@ -98,6 +98,10 @@ pub enum ClaudeMessage {
         /// Output style hint from Claude Code (v2.1.81+). Informational only.
         #[serde(default)]
         output_style: Option<String>,
+        /// Plugin errors from Claude Code (v2.1.111+). Populated when plugins are demoted
+        /// due to unsatisfied dependencies.
+        #[serde(default)]
+        plugin_errors: Option<serde_json::Value>,
     },
     #[serde(rename = "assistant")]
     Assistant {
@@ -330,6 +334,14 @@ pub struct PostCompactEvent {
     pub conversation_id: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PreCompactEvent {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub session_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CwdChangedEvent {
     pub cwd: String,
@@ -790,6 +802,30 @@ mod tests {
         assert!(!serialized.contains("conversation_id"));
     }
 
+    #[test]
+    fn test_pre_compact_event_serialization() {
+        let event = PreCompactEvent {
+            session_id: Some("sess-abc".to_string()),
+            conversation_id: Some("conv-123".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"session_id\":\"sess-abc\""));
+        assert!(serialized.contains("\"conversation_id\":\"conv-123\""));
+    }
+
+    #[test]
+    fn test_pre_compact_event_omits_none_fields() {
+        let event = PreCompactEvent {
+            session_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(!serialized.contains("session_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
+
     #[test]
     fn test_cwd_changed_event_serialization() {
         let event = CwdChangedEvent {
@@ -945,6 +981,44 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_system_init_with_plugin_errors() {
+        let json = r#"{"type":"system","subtype":"init","session_id":"sess-1","plugin_errors":["Plugin 'foo' requires 'bar' which is not installed","Plugin 'baz' failed to load"]}"#;
+        let msg: ClaudeMessage = serde_json::from_str(json).unwrap();
+        if let ClaudeMessage::System { plugin_errors, .. } = msg {
+            let errors = plugin_errors.expect("plugin_errors should be present");
+            let arr = errors.as_array().expect("plugin_errors should be an array");
+            assert_eq!(arr.len(), 2);
+            assert_eq!(arr[0].as_str(), Some("Plugin 'foo' requires 'bar' which is not installed"));
+        } else {
+            panic!("Expected System variant");
+        }
+    }
+
+    #[test]
+    fn test_system_init_without_plugin_errors() {
+        let json = r#"{"type":"system","subtype":"init","session_id":"sess-1"}"#;
+        let msg: ClaudeMessage = serde_json::from_str(json).unwrap();
+        if let ClaudeMessage::System { plugin_errors, .. } = msg {
+            assert!(plugin_errors.is_none());
+        } else {
+            panic!("Expected System variant");
+        }
+    }
+
+    #[test]
+    fn test_system_init_with_empty_plugin_errors() {
+        let json = r#"{"type":"system","subtype":"init","session_id":"sess-1","plugin_errors":[]}"#;
+        let msg: ClaudeMessage = serde_json::from_str(json).unwrap();
+        if let ClaudeMessage::System { plugin_errors, .. } = msg {
+            let errors = plugin_errors.expect("plugin_errors should be present");
+            let arr = errors.as_array().expect("plugin_errors should be an array");
+            assert!(arr.is_empty());
+        } else {
+            panic!("Expected System variant");
+        }
+    }
+
     #[test]
     fn test_result_message_with_fast_mode_state() {
         let json = r#"{"type":"result","subtype":"success","fast_mode_state":"enabled"}"#;