feat: migrate mode and cache_mode fields to buffer system

- Add cache_mode field to Buffer struct with BufferAPI methods
- Add wrapper methods is_cache_mode() and set_cache_mode()
- Update all 6 cache_mode references to use wrapper methods
- Add cache_mode to buffer debug output

- Migrate mode field using existing wrapper methods
- Update all 52+ mode references to use get_mode() and set_mode()
- Replace direct assignments with set_mode() calls
- Replace match/comparison statements with get_mode() calls

Both fields now properly use buffer system for per-buffer state management.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: TimelordUK

sql-cli/PHASE2_MIGRATION_PLAN.md

@@ -17,7 +17,7 @@ These are buffer-specific and should move:
 - `textarea` - Multi-line editor for this buffer
 - `results` - Query results for this buffer
 - ✅ `table_state` - Table selection state **[DONE - Wrapper added, tested, working]**
-- `mode` - Current mode (Command/Results/etc) for this buffer
+- ✅ `mode` - Current mode (Command/Results/etc) for this buffer **[DONE - Using existing wrapper methods]**
 - ✅ `status_message` - Status message for current buffer **[DONE - Fully migrated]**
 
 #### Filtering/Search State
@@ -82,7 +82,7 @@ These are truly application-wide:
 
 ### 🟡 Needs Discussion
 These could go either way:
-- `cache_mode` - Could be global or per-buffer
+- ✅ `cache_mode` - Could be global or per-buffer **[DONE - Migrated to buffer system]**
 - `last_visible_rows` - Viewport tracking, probably per-buffer
 
 ## Migration Status

sql-cli/src/buffer.rs

@@ -215,6 +215,8 @@ pub trait BufferAPI {
     fn get_csv_client_mut(&mut self) -> Option<&mut CsvApiClient>;
     fn is_csv_mode(&self) -> bool;
     fn get_table_name(&self) -> String;
+    fn is_cache_mode(&self) -> bool;
+    fn set_cache_mode(&mut self, cache_mode: bool);
 
     // --- Input State ---
     fn get_input_value(&self) -> String;
@@ -253,6 +255,7 @@ pub struct Buffer {
     pub csv_client: Option<CsvApiClient>,
     pub csv_mode: bool,
     pub csv_table_name: String,
+    pub cache_mode: bool,
     pub results: Option<QueryResponse>,
     pub cached_data: Option<Vec<serde_json::Value>>,
 
@@ -571,6 +574,14 @@ impl BufferAPI for Buffer {
         self.csv_table_name.clone()
     }
 
+    fn is_cache_mode(&self) -> bool {
+        self.cache_mode
+    }
+
+    fn set_cache_mode(&mut self, cache_mode: bool) {
+        self.cache_mode = cache_mode;
+    }
+
     // --- Input State ---
     fn get_input_value(&self) -> String {
         self.input.value().to_string()
@@ -722,6 +733,7 @@ impl BufferAPI for Buffer {
         output.push_str("\n--- CSV/Data Source ---\n");
         output.push_str(&format!("CSV Mode: {}\n", self.csv_mode));
         output.push_str(&format!("CSV Table Name: '{}'\n", self.csv_table_name));
+        output.push_str(&format!("Cache Mode: {}\n", self.cache_mode));
         output.push_str(&format!("Has CSV Client: {}\n", self.csv_client.is_some()));
         output.push_str(&format!(
             "Has Cached Data: {}\n",
@@ -770,6 +782,7 @@ impl Buffer {
             csv_client: None,
             csv_mode: false,
             csv_table_name: String::new(),
+            cache_mode: false,
             results: None,
             cached_data: None,