Update documentation and add session management features

- Revise keymap documentation to include immediate updates
- Add session management: auto-load and auto-save Session.vim

lua/autocmds.lua

@@ -99,4 +99,35 @@ vim.api.nvim_create_autocmd("FileType", {
 	end,
 })
 
+-- Session management: auto-load on startup, auto-save on exit (only if Session.vim exists)
+local session_aug = vim.api.nvim_create_augroup("SessionManagement", { clear = true })
+
+-- Auto-load Session.vim if it exists in the current directory
+vim.api.nvim_create_autocmd("VimEnter", {
+	group = session_aug,
+	pattern = "*",
+	nested = true, -- Allow other autocmds to fire after loading session
+	callback = function()
+		-- Only auto-load if:
+		-- 1. Session.vim exists in cwd
+		-- 2. No files were specified on command line (vim.fn.argc() == 0)
+		-- 3. Not started with nvim -S (check if we already loaded a session)
+		if vim.fn.argc() == 0 and vim.fn.filereadable("Session.vim") == 1 and vim.v.this_session == "" then
+			vim.cmd("source Session.vim")
+		end
+	end,
+})
+
+-- Auto-save session on exit, but ONLY if Session.vim already exists
+vim.api.nvim_create_autocmd("VimLeavePre", {
+	group = session_aug,
+	pattern = "*",
+	callback = function()
+		-- Only save if Session.vim exists (user manually created it)
+		if vim.fn.filereadable("Session.vim") == 1 then
+			vim.cmd("mksession! Session.vim")
+		end
+	end,
+})
+
 return {}