Add Re-attach for a relaunched same-name target

In the Terminated state the Injection panel now offers a Re-attach button: it
refreshes the process list and finds live processes whose image name matches the
original target's (case-insensitive). Exactly one match -> tear down the stale IPC
channel and inject into the new pid via the normal path; several matches -> don't
guess, filter the picker to the name and prompt the operator to pick one; none ->
report it. Saves hunting for a relaunched game's new pid in the list.

Verified: x64 build + ctest 7/7 green. Re-attach is a Terminated-state button flow,
so its end-to-end behavior is best confirmed live (ImGui clicks can't be scripted);
logic reviewed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

host/src/injection_panel.cpp

@@ -28,6 +28,24 @@ std::string narrow(const std::wstring& w)
 	return out;
 }
 
+// Case-insensitive equality of two image names (e.g. "snb.exe").
+bool iequals_name(const std::wstring& a, const std::wstring& b)
+{
+	const std::string x = narrow(a), y = narrow(b);
+	if (x.size() != y.size())
+	{
+		return false;
+	}
+	for (std::size_t i = 0; i < x.size(); ++i)
+	{
+		if (::tolower(static_cast<unsigned char>(x[i])) != ::tolower(static_cast<unsigned char>(y[i])))
+		{
+			return false;
+		}
+	}
+	return true;
+}
+
 bool contains_ci(const std::wstring& haystack, const char* needle_utf8)
 {
 	if (needle_utf8 == nullptr || needle_utf8[0] == '\0')
@@ -183,6 +201,50 @@ void InjectionPanel::inject_selected()
 	}
 }
 
+void InjectionPanel::reattach()
+{
+	if (selected_name_.empty())
+	{
+		return;
+	}
+
+	// Find live processes that share the original target's image name.
+	refresh_processes();
+	std::vector<unsigned long> matches;
+	for (const ProcessEntry& e : processes_)
+	{
+		if (iequals_name(e.exe_name, selected_name_))
+		{
+			matches.push_back(e.pid);
+		}
+	}
+
+	const std::string name = narrow(selected_name_);
+	if (matches.empty())
+	{
+		status_ = "No running \"" + name + "\" to re-attach to.";
+		status_color_ = kRed;
+		return;
+	}
+	if (matches.size() > 1)
+	{
+		// Don't guess which instance: filter the picker to the matches so the operator
+		// chooses, then injects via the normal button.
+		snprintf(filter_, sizeof(filter_), "%s", name.c_str());
+		selected_pid_ = 0;
+		status_ = "Multiple \"" + name + "\" running -- pick one below, then Inject & Connect.";
+		status_color_ = kGrey;
+		return;
+	}
+
+	// Exactly one: tear down the stale channel and inject into the new pid.
+	server_.stop();
+	close_target_handle();
+	injected_ = false;
+	selected_pid_ = matches.front();
+	inject_selected();
+}
+
 void InjectionPanel::publish(const std::array<PadInfo, kMaxPads>& pads)
 {
 	if (!test_input_)
@@ -430,6 +492,18 @@ void InjectionPanel::draw(bool debug_details)
 			status_ = "Stopped.";
 			status_color_ = kGrey;
 		}
+		// A relaunched game has a new pid; re-attach by image name without hunting for
+		// it in the list. Only offered once the old target is gone.
+		if (target_state_ == TargetState::Terminated && !selected_name_.empty())
+		{
+			ImGui::SameLine();
+			if (ImGui::Button("Re-attach"))
+			{
+				reattach();
+			}
+			ImGui::SameLine();
+			ImGui::TextDisabled("(relaunched %s)", narrow(selected_name_).c_str());
+		}
 		ImGui::Separator();
 	}