feat(snacks): add snacks.picker action integration

lua/opencode/integrations/picker/snacks.lua

@@ -0,0 +1,27 @@
+---@module 'snacks'
+
+---Snacks picker integration for opencode.
+---@class opencode.integrations.picker.snacks
+local M = {}
+
+---Send selected picker items to opencode prompt.
+---@param picker snacks.Picker
+function M.opencode_send(picker)
+  local Context = require("opencode.context")
+  local entries = {}
+  for _, item in ipairs(picker:selected({ fallback = true })) do
+    entries[#entries + 1] = Context.format({
+      path = item.text,
+      start_line = item.pos and item.pos[1] or nil,
+      start_col = item.pos and item.pos[2] or nil,
+      end_line = item.end_pos and item.end_pos[1] or nil,
+      end_col = item.end_pos and item.end_pos[2] or nil,
+    })
+  end
+  if #entries == 0 then
+    return
+  end
+  require("opencode").prompt(table.concat(entries, "\n"))
+end
+
+return M