subagents extension on the generic host surfaces

The rock now owns all subagent policy on top of libpanto-lua's generic APIs:
children are ordinary panto.agent instances over rock-constructed stores,
started with agent:run_async and awaited by arming uv.new_poll on each job's
wake_fd from the tool handler's coroutine.

subagents/jobs.lua carries the session policy the host used to own: the
concurrency gate (4 running, FIFO queue, cancel-while-queued never starts),
the await contract (results in input order; "first" returns settled plus
remaining by identity), and settle-time shaping. subagents/spawn.lua seeds
new children (primary system context, child role, profile body with manifest
metadata), resolves model/reasoning through panto.ext.resolve_model, filters
subagents.* out of the inherited tool set via agent:set_tools, and reads
resume defaults back from stored message metadata. One-shot structured
workers are a null_store agent with a declaration-only output tool,
tool_choice forced, dispatch_tools=false. subagents/progress.lua renders
per-tool-entry cards through the component handle's invalidate seam;
turn_interrupt cancels live children, turn_end closes them.

Spec suite rewritten against fakes of the new surfaces (98 cases), including
gate/queue/cancel bounds, resume-default extraction, one-shot capture via
unresolved tool calls, tool filtering, and manifest seeding.

1 files changed, 84 insertions, 0 deletions

diff --git a/panto-subagents-0.1.0-1.rockspec b/panto-subagents-0.1.0-1.rockspec
new file mode 100644
index 0000000..073ff56
--- /dev/null
+++ b/panto-subagents-0.1.0-1.rockspec
@@ -0,0 +1,84 @@
+-- LuaRocks rockspec for `panto-subagents`: the `subagents` extension for
+-- Pantograph — pure Lua, no compiled artifact of its own.
+--
+-- Module naming. Pantograph requires the first whitespace-delimited token of an
+-- `[extensions] rocks = [...]` entry, so `require("panto-subagents")` must
+-- resolve to this rock's entry point; that is what the first `modules` line
+-- maps. The remaining modules keep the same `subagents.<name>` paths a local
+-- checkout gets from `paths = ["/path/to/panto-subagents"]`, so both load paths
+-- resolve identical requires.
+--
+-- Dependencies. `lyaml` parses profile frontmatter and is a C binding over the
+-- system libyaml, which luarocks does not vendor: a machine without it needs
+-- `brew install libyaml` (or `apt install libyaml-dev`) first, and may need
+-- `YAML_DIR=...` passed to luarocks. `toml2lua` (module name `toml`) reads TOML
+-- workflows and is pure Lua. `luv` backs the recursive discovery walk and the
+-- wake pipes child jobs are polled on, and ships with panto as a pinned
+-- battery, so it is normally already present in the tree this rock installs
+-- into.
+--
+-- Deliberately absent: `jsonschema`. It validates structured workflow output
+-- when installed, and subagents/workflow.lua uses it if `require` finds it, but
+-- it depends on `lrexlib-pcre`, which needs a system PCRE that stock macOS does
+-- not have. A failed dependency install would take the whole extension down
+-- silently (panto logs and skips a rock that fails to load), so the built-in
+-- subset validator is the default and `jsonschema` stays opt-in.
+
+rockspec_format = "3.0"
+package = "panto-subagents"
+version = "0.1.0-1"
+
+source = {
+    url = "git+https://github.com/travisp/panto-subagents",
+}
+
+description = {
+    summary = "Delegation and workflows for Pantograph: the `subagents` extension.",
+    detailed = [[
+        Lets a primary panto agent start specialized child agents from Markdown
+        profiles, run several at once, and continue their conversations later.
+        Provides the subagents.run / subagents.models / subagents.lua /
+        subagents.workflow tools, a callback-based Lua workflow API with
+        one-shot structured workers, and TOML dependency graphs exposed as
+        /workflow:<name> commands.
+    ]],
+    homepage = "https://github.com/travisp/panto-subagents",
+    license = "MIT",
+    labels = { "ai", "llm", "agent", "panto", "pantograph", "extension" },
+}
+
+dependencies = {
+    "lua >= 5.4, < 5.5",
+    "lyaml >= 6.2, < 7.0",
+    "toml2lua >= 3.0, < 4.0",
+    "luv >= 1.48",
+}
+
+-- The specs run on plain Lua and decode structured child output with dkjson
+-- when the host's own JSON codec (`panto.ext.json`) is absent.
+test_dependencies = {
+    "dkjson >= 2.11",
+}
+
+test = {
+    type = "command",
+    command = "lua spec/run.lua",
+}
+
+build = {
+    type = "builtin",
+    modules = {
+        ["panto-subagents"] = "init.lua",
+        ["subagents.frontmatter"] = "subagents/frontmatter.lua",
+        ["subagents.jobs"] = "subagents/jobs.lua",
+        ["subagents.luatool"] = "subagents/luatool.lua",
+        ["subagents.models"] = "subagents/models.lua",
+        ["subagents.paths"] = "subagents/paths.lua",
+        ["subagents.profiles"] = "subagents/profiles.lua",
+        ["subagents.progress"] = "subagents/progress.lua",
+        ["subagents.run"] = "subagents/run.lua",
+        ["subagents.spawn"] = "subagents/spawn.lua",
+        ["subagents.toml_workflows"] = "subagents/toml_workflows.lua",
+        ["subagents.workflow"] = "subagents/workflow.lua",
+    },
+}