feat: make ares self-contained workspace with bundled domain/mt5-client crates

Vendor domain and mt5-client from hermes into crates/ so the repo can
be pushed to GitHub without external path dependencies.

Also includes all bug fixes from autonomous session:
- impulse SL fix (SL at impulse candle low/high, not zone edge)
- pip_size fix for 5-decimal pairs
- fill_ok premature cancellation fix
- TIMEOUT_CANDLES, MIN_FVG_PIPS, MIN_SL_PIPS env vars

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

crates/mt5-client/src/error.rs

@@ -0,0 +1,14 @@
+#[derive(Debug, thiserror::Error)]
+pub enum Mt5Error {
+    #[error("request failed: {0}")]
+    Http(#[from] reqwest::Error),
+
+    #[error("bridge error ({status}): {detail}")]
+    Api { status: u16, detail: String },
+
+    #[error("response parse failed: {0}")]
+    Parse(#[from] serde_json::Error),
+
+    #[error("empty response for {endpoint}")]
+    Empty { endpoint: String },
+}