refactor: Restructure keymaps and event handlers into centralized config-driven system

- Add M.setup() to cmd module for configuration
    - Move describe editor config to M.config.describe.editor with nested structure
    - Add keymaps config with separate log, status, and close sections
    - Implement resolve_keymaps_from_specs() helper to build keymap lists from config
    - Extract editor.open_editor() keymaps parameter support
    - Move status/log event handlers from terminal.lua to cmd.lua
    - Convert log/status buffer keymaps to config-driven approach with handler specs

lua/jj/init.lua

@@ -7,6 +7,8 @@ local utils = require("jj.utils")
 
 --- Jujutsu plugin configuration
 --- @class jj.Config
+--- @field cmd? jj.cmd.opts Options for command module
+--- @field picker? jj.picker.config Options for picker module
 M.config = {
 	-- Default configuration
 	--- @type jj.picker.config
@@ -20,8 +22,6 @@ M.config = {
 		deleted = { fg = "#f85149", ctermfg = "Red" },
 		renamed = { fg = "#d29922", ctermfg = "Yellow" },
 	},
-	--- @type "buffer"|"input" Editor mode for describe command: "buffer" (Git-style editor) or "input" (simple input prompt)
-	describe_editor = "buffer",
 }
 
 --- Setup the plugin
@@ -32,13 +32,9 @@ function M.setup(opts)
 	-- Setup for sub-modules
 	picker.setup(opts and opts.picker or {})
 	editor.setup({ highlights = M.config.highlights })
+	cmd.setup(opts.cmd)
 	utils.setup(opts) -- Keep for future-proofing, even if it's a no-op now
 
-	-- Pass describe_editor config to cmd module
-	if opts and opts.describe_editor then
-		cmd.config.describe_editor = opts.describe_editor
-	end
-
 	cmd.register_command()
 
 	-- Expose public API functions on the top-level module