refactor: reorganize tests/tools, share python protocol helpers

crates/pipeview-client/tests/fixtures/lua_line_framer.lua

@@ -0,0 +1,43 @@
+local buffer = ""
+
+return {
+    feed = function(bytes)
+        buffer = buffer .. bytes
+        local frames = {}
+
+        while true do
+            local i = buffer:find("\n", 1, true)
+            if not i then
+                break
+            end
+
+            local frame = buffer:sub(1, i - 1)
+            if frame:sub(-1) == "\r" then
+                frame = frame:sub(1, -2)
+            end
+
+            frames[#frames + 1] = frame
+            buffer = buffer:sub(i + 1)
+        end
+
+        return frames
+    end,
+
+    flush = function()
+        if #buffer == 0 then
+            return nil
+        end
+
+        local frame = buffer
+        buffer = ""
+        return frame
+    end,
+
+    reset = function()
+        buffer = ""
+    end,
+
+    pending_len = function()
+        return #buffer
+    end,
+}