Persist config files across Opus package updates

The Opus package manager deletes the entire package directory on
update (fs.delete(packageDir)) before re-downloading files. This
wiped all config files (.manager_config, .client_config, etc.) that
were stored inside packages/inventory-manager/.

Fix: add _configPath() helper to every program that resolves config
file paths to usr/config/inventory-manager/ when running under Opus,
which lives outside the package directory and survives updates.
Falls back to the local _path() for standalone (non-Opus) use.

Updated files:
- inventoryManager.lua, manager/config.lua, inventoryClient.lua,
  inventoryWebBridge.lua, dropperController.lua, craftingTurtle.lua
- .package install script: saves configs to usr/config/inventory-manager/
- autorun/startup.lua: checks both persistent and package dirs
- startup/client.lua: uses persistent dir for .client_setup/.dropper_config
- web/server/Dockerfile: switch health check to wget (from prior fix)

manager/config.lua

@@ -22,9 +22,9 @@ C.SMELT_RESERVE     = 128
 C.DEFRAG_INTERVAL   = 600
 C.COMPOST_INTERVAL  = 3
 C.ALERT_INTERVAL    = 15
-C.CACHE_FILE        = _path(".inventory_cache")
+C.CACHE_FILE        = _configPath(".inventory_cache")
 C.SMELTER_MONITOR_SIDE = "top"
-C.DISABLED_RECIPES_FILE = _path(".disabled_recipes")
+C.DISABLED_RECIPES_FILE = _configPath(".disabled_recipes")
 
 -- Network
 C.BROADCAST_CHANNEL  = 4200
@@ -71,7 +71,17 @@ C.SLOT_OUTPUT = 3
 -- Config file loader
 -------------------------------------------------
 
-local CONFIG_FILE = _path(".manager_config")
+-- Persistent config path: survives Opus package updates
+local _PERSIST_DIR = "usr/config/inventory-manager"
+local function _configPath(rel)
+    if fs.isDir(_PERSIST_DIR) or fs.isDir("packages/inventory-manager") then
+        if not fs.isDir(_PERSIST_DIR) then fs.makeDir(_PERSIST_DIR) end
+        return fs.combine(_PERSIST_DIR, rel)
+    end
+    return _path(rel)
+end
+
+local CONFIG_FILE = _configPath(".manager_config")
 
 function C.loadConfig()
     if not fs.exists(CONFIG_FILE) then return end
@@ -124,7 +134,7 @@ C.LOW_STOCK_ALERTS = dofile(_path("data/alerts.lua"))
 
 -- Recipe book: merges built-in recipes + user-learned recipes
 local recipeBook   = dofile(_path("lib/recipeBook.lua"))
-recipeBook.init(_path(".recipes.db"))
+recipeBook.init(_configPath(".recipes.db"))
 recipeBook.loadLegacyCrafting(dofile(_path("data/craftable.lua")))
 recipeBook.loadLegacySmelting(dofile(_path("data/smeltable.lua")))
 C.recipeBook = recipeBook