fix(memory): prevent autosave key collisions across runtime flows

Fixes #221 - SQLite Memory Override bug.

This PR resolves memory overwrite behavior in autosave paths by replacing fixed memory keys with unique keys, and improves short-horizon recall quality in channel runtime.

**Root Cause**
SQLite memory uses a unique constraint on `memories.key` and writes with `ON CONFLICT(key) DO UPDATE`.
Several autosave paths reused fixed keys (or sender-stable keys), so newer messages overwrote earlier conversation entries.

**Changes**
- Channel runtime: autosave key changed from `channel_sender` to `channel_sender_messageId`
- Added memory-context injection before provider calls (aligned with agent loop behavior)
- Agent loop: autosave keys changed from fixed `user_msg`/`assistant_resp` to UUID-suffixed keys
- Gateway: Webhook/WhatsApp autosave keys changed to UUID-suffixed keys

All CI checks passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/agent/loop_.rs

@@ -11,6 +11,7 @@ use std::fmt::Write;
 use std::io::Write as IoWrite;
 use std::sync::Arc;
 use std::time::Instant;
+use uuid::Uuid;
 
 /// Maximum agentic tool-use iterations per user message to prevent runaway loops.
 const MAX_TOOL_ITERATIONS: usize = 10;
@@ -19,6 +20,10 @@ const MAX_TOOL_ITERATIONS: usize = 10;
 /// When exceeded, the oldest messages are dropped (system prompt is always preserved).
 const MAX_HISTORY_MESSAGES: usize = 50;
 
+fn autosave_memory_key(prefix: &str) -> String {
+    format!("{prefix}_{}", Uuid::new_v4())
+}
+
 /// Trim conversation history to prevent unbounded growth.
 /// Preserves the system prompt (first message if role=system) and the most recent messages.
 fn trim_history(history: &mut Vec<ChatMessage>) {
@@ -90,7 +95,9 @@ fn parse_tool_calls(response: &str) -> (String, Vec<ParsedToolCall>) {
                         .to_string();
 
                     // Arguments in OpenAI format are a JSON string that needs parsing
-                    let arguments = if let Some(args_str) = function.get("arguments").and_then(|v| v.as_str()) {
+                    let arguments = if let Some(args_str) =
+                        function.get("arguments").and_then(|v| v.as_str())
+                    {
                         serde_json::from_str::<serde_json::Value>(args_str)
                             .unwrap_or(serde_json::Value::Object(serde_json::Map::new()))
                     } else {
@@ -182,11 +189,7 @@ async fn agent_turn(
         if tool_calls.is_empty() {
             // No tool calls — this is the final response
             history.push(ChatMessage::assistant(&response));
-            return Ok(if text.is_empty() {
-                response
-            } else {
-                text
-            });
+            return Ok(if text.is_empty() { response } else { text });
         }
 
         // Print any text the LLM produced alongside tool calls
@@ -235,9 +238,7 @@ async fn agent_turn(
 
         // Add assistant message with tool calls + tool results to history
         history.push(ChatMessage::assistant(&response));
-        history.push(ChatMessage::user(format!(
-            "[Tool results]\n{tool_results}"
-        )));
+        history.push(ChatMessage::user(format!("[Tool results]\n{tool_results}")));
     }
 
     anyhow::bail!("Agent exceeded maximum tool iterations ({MAX_TOOL_ITERATIONS})")
@@ -252,7 +253,8 @@ fn build_tool_instructions(tools_registry: &[Box<dyn Tool>]) -> String {
     instructions.push_str("```\n<tool_call>\n{\"name\": \"tool_name\", \"arguments\": {\"param\": \"value\"}}\n</tool_call>\n```\n\n");
     instructions.push_str("You may use multiple tool calls in a single response. ");
     instructions.push_str("After tool execution, results appear in <tool_result> tags. ");
-    instructions.push_str("Continue reasoning with the results until you can give a final answer.\n\n");
+    instructions
+        .push_str("Continue reasoning with the results until you can give a final answer.\n\n");
     instructions.push_str("### Available Tools\n\n");
 
     for tool in tools_registry {
@@ -397,8 +399,9 @@ pub async fn run(
     if let Some(msg) = message {
         // Auto-save user message to memory
         if config.memory.auto_save {
+            let user_key = autosave_memory_key("user_msg");
             let _ = mem
-                .store("user_msg", &msg, MemoryCategory::Conversation)
+                .store(&user_key, &msg, MemoryCategory::Conversation)
                 .await;
         }
 
@@ -429,8 +432,9 @@ pub async fn run(
         // Auto-save assistant response to daily log
         if config.memory.auto_save {
             let summary = truncate_with_ellipsis(&response, 100);
+            let response_key = autosave_memory_key("assistant_resp");
             let _ = mem
-                .store("assistant_resp", &summary, MemoryCategory::Daily)
+                .store(&response_key, &summary, MemoryCategory::Daily)
                 .await;
         }
     } else {
@@ -451,8 +455,9 @@ pub async fn run(
         while let Some(msg) = rx.recv().await {
             // Auto-save conversation turns
             if config.memory.auto_save {
+                let user_key = autosave_memory_key("user_msg");
                 let _ = mem
-                    .store("user_msg", &msg.content, MemoryCategory::Conversation)
+                    .store(&user_key, &msg.content, MemoryCategory::Conversation)
                     .await;
             }
 
@@ -489,8 +494,9 @@ pub async fn run(
 
             if config.memory.auto_save {
                 let summary = truncate_with_ellipsis(&response, 100);
+                let response_key = autosave_memory_key("assistant_resp");
                 let _ = mem
-                    .store("assistant_resp", &summary, MemoryCategory::Daily)
+                    .store(&response_key, &summary, MemoryCategory::Daily)
                     .await;
             }
         }
@@ -510,6 +516,8 @@ pub async fn run(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::memory::{Memory, MemoryCategory, SqliteMemory};
+    use tempfile::TempDir;
 
     #[test]
     fn parse_tool_calls_extracts_single_call() {
@@ -646,12 +654,9 @@ After text."#;
         assert_eq!(history[0].content, "system prompt");
         // Trimmed to limit
         assert_eq!(history.len(), MAX_HISTORY_MESSAGES + 1); // +1 for system
-        // Most recent messages preserved
+                                                             // Most recent messages preserved
         let last = &history[history.len() - 1];
-        assert_eq!(
-            last.content,
-            format!("msg {}", MAX_HISTORY_MESSAGES + 19)
-        );
+        assert_eq!(last.content, format!("msg {}", MAX_HISTORY_MESSAGES + 19));
     }
 
     #[test]
@@ -664,4 +669,35 @@ After text."#;
         trim_history(&mut history);
         assert_eq!(history.len(), 3);
     }
+
+    #[test]
+    fn autosave_memory_key_has_prefix_and_uniqueness() {
+        let key1 = autosave_memory_key("user_msg");
+        let key2 = autosave_memory_key("user_msg");
+
+        assert!(key1.starts_with("user_msg_"));
+        assert!(key2.starts_with("user_msg_"));
+        assert_ne!(key1, key2);
+    }
+
+    #[tokio::test]
+    async fn autosave_memory_keys_preserve_multiple_turns() {
+        let tmp = TempDir::new().unwrap();
+        let mem = SqliteMemory::new(tmp.path()).unwrap();
+
+        let key1 = autosave_memory_key("user_msg");
+        let key2 = autosave_memory_key("user_msg");
+
+        mem.store(&key1, "I'm Paul", MemoryCategory::Conversation)
+            .await
+            .unwrap();
+        mem.store(&key2, "I'm 45", MemoryCategory::Conversation)
+            .await
+            .unwrap();
+
+        assert_eq!(mem.count().await.unwrap(), 2);
+
+        let recalled = mem.recall("45", 5).await.unwrap();
+        assert!(recalled.iter().any(|entry| entry.content.contains("45")));
+    }
 }