Show full subagents.lua source when expanded; guide toward templated promptsHEADmain

The expanded progress board capped the executed Lua at 128 lines (and 32KB),
so long workflow sources ended in an ellipsis even after Ctrl-O. Expanded
now renders the whole source; collapsed still shows the first four lines.

Add a "Program, don't transcribe" section to the system guidance so the
primary writes shorter sources: one [[template]] with {name} placeholders
filled by gsub with a table, loops over data instead of per-child copies,
shared system prompts in `agents`, and file references instead of quoted
contents. A single templating mechanism is named on purpose to remove
choice.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ETqhv5FVD8Z14BEBsXeHHC

1 files changed, 23 insertions, 0 deletions

diff --git a/spec/test_progress.lua b/spec/test_progress.lua
index 79570c1..a562789 100644
--- a/spec/test_progress.lua
+++ b/spec/test_progress.lua
@@ -349,6 +349,29 @@ return {
         progress.reset()
     end },
 
+    { "expanded subagents.lua source is never truncated", function()
+        if not pcall(require, "dkjson") then return "skip", "dkjson is not installed" end
+        progress.reset()
+        local lines = {}
+        for i = 1, 600 do lines[i] = "local v" .. i .. " = " .. i end
+        lines[#lines + 1] = "return 'last-line'"
+        local component
+        progress.claim({
+            id = "call-long-source",
+            tool_name = "subagents.lua",
+            collapsed = false,
+            input = require("dkjson").encode({ source = table.concat(lines, "\n") }),
+            set_component = function(_, value)
+                component = value
+                return { invalidate = function() end, alive = function() return true end }
+            end,
+        })
+        local rendered = component:render(100)
+        assert(rendered[#rendered] == "    return 'last-line'", rendered[#rendered])
+        assert(#rendered == 2 + #lines, #rendered)
+        progress.reset()
+    end },
+
     { "expanded history includes streamed assistant text and available tool call fields", function()
         progress.reset()
         local component = board("call-tools", false)