Simplify system prompt: remove coding style and parallel tool call sections

- Remove IMPORTANT FOR CODING section (~1,500 chars of coding guidelines)
- Remove <use_parallel_tool_calls> block (~500 chars)
- Remove unused const_format dependency from g3-core
- Simplify get_system_prompt_for_native() to just return base prompt
- Response Guidelines now cleanly ends the static prompt

Prompt reduced from ~8,500 to ~6,500 characters.

crates/g3-core/src/tool_dispatch.rs

@@ -7,7 +7,7 @@ use anyhow::Result;
 use tracing::{debug, warn};
 
 use crate::tools::executor::ToolContext;
-use crate::tools::{file_ops, misc, research, shell, todo, webdriver};
+use crate::tools::{file_ops, memory, misc, research, shell, todo, webdriver};
 use crate::ui_writer::UiWriter;
 use crate::ToolCall;
 
@@ -44,6 +44,9 @@ pub async fn dispatch_tool<W: UiWriter>(
         // Research tool
         "research" => research::execute_research(tool_call, ctx).await,
 
+        // Project memory tools
+        "remember" => memory::execute_remember(tool_call, ctx).await,
+
         // WebDriver tools
         "webdriver_start" => webdriver::execute_webdriver_start(tool_call, ctx).await,
         "webdriver_navigate" => webdriver::execute_webdriver_navigate(tool_call, ctx).await,