heph.nvim: plug-and-play managed daemon (autostart, self-heal, client/server guardrail)

The plugin now manages its own hephd by default (autostart = true): if nothing
is serving the socket it spawns a local daemon against the default XDG paths,
kills only what it spawned on VimLeavePre, and self-heals — rpc.call retries
once through a respawn hook when the connection drops (the prior owner releases
the DB lock on exit, so a respawn can claim it).

- daemon.ensure() connects to an already-running daemon (any mode) or spawns one
  we own; stop_spawned()/is_managed() track lifecycle.
- A server/client daemon you started is always respected (spawn only when nothing
  serves the socket). autostart = false → connect-only, warns/errors if down,
  and clears the self-heal hook so it fails loudly.
- config: autostart defaults true; new `db` option; $HEPH_SOCKET / $HEPH_DB
  fallbacks isolate a dev Neovim onto a separate daemon + DB.

e2e: managed_daemon_spec covers autostart spawn, self-heal-after-kill, and
connect-only error. 10 specs green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

heph.nvim/lua/heph/init.lua

@@ -14,15 +14,44 @@ M.config = nil
 function M.setup(opts)
   local cfg = vim.tbl_deep_extend("force", config.defaults, opts or {})
   cfg.socket = config.resolve_socket(cfg.socket)
+  cfg.db = config.resolve_db(cfg.db)
   M.config = cfg
 
-  require("heph.rpc").setup(cfg.socket)
+  local rpc = require("heph.rpc")
+  local daemon = require("heph.daemon")
+  rpc.setup(cfg.socket)
 
   if cfg.autostart then
-    local ok = require("heph.daemon").wait_ready(cfg.socket, 500)
+    -- Plug-and-play: bring up a managed local daemon if none is serving, and
+    -- self-heal a dropped connection on later calls.
+    local ok = pcall(daemon.ensure, {
+      socket = cfg.socket,
+      db = cfg.db,
+      bin = cfg.bin,
+      autostart = true,
+    })
     if not ok then
-      require("heph.daemon").spawn({ bin = cfg.bin, socket = cfg.socket, db = nil })
-      require("heph.daemon").wait_ready(cfg.socket, 5000)
+      require("heph.util").notify(
+        "could not start hephd; will retry on first use",
+        vim.log.levels.WARN
+      )
+    end
+    rpc.set_respawn(function()
+      pcall(daemon.ensure, {
+        socket = cfg.socket,
+        db = cfg.db,
+        bin = cfg.bin,
+        autostart = true,
+      })
+    end)
+  else
+    -- Explicit architecture: connect only, never spawn over the user's daemon.
+    rpc.set_respawn(nil)
+    if not daemon.ensure({ socket = cfg.socket, autostart = false }) then
+      require("heph.util").notify(
+        "no hephd reachable at " .. cfg.socket .. " (autostart disabled)",
+        vim.log.levels.WARN
+      )
     end
   end