fix(git): validate placement, cache repo lookups, tighten lifecycle

lua/git/repo.lua

@@ -204,6 +204,7 @@ function Repo:close()
     end
     self._watchers = {}
     self._refresh_handle.close()
+    self._events:clear()
 end
 
 ---@param event ow.Git.Repo.Event
@@ -344,6 +345,9 @@ end
 ---@type table<string, ow.Git.Repo> keyed by worktree
 local repos = {}
 
+---@type table<string, true>
+local no_repo_dirs = {}
+
 ---@param event ow.Git.Repo.Event
 ---@param fn fun(...)
 ---@return fun() unsubscribe
@@ -440,8 +444,13 @@ function M.resolve(arg)
     else
         path = path_for_buf(expand_buf(arg))
     end
+    local dir = vim.fs.dirname(path)
+    if no_repo_dirs[dir] then
+        return nil
+    end
     local found = vim.fs.find(".git", { upward = true, path = path })[1]
     if not found then
+        no_repo_dirs[dir] = true
         return nil
     end
     local worktree = vim.fs.dirname(found)
@@ -473,6 +482,11 @@ function M.resolve(arg)
     end
     local r = Repo.new(gitdir, worktree)
     repos[worktree] = r
+    for d in pairs(no_repo_dirs) do
+        if d == worktree or vim.startswith(d, worktree .. "/") then
+            no_repo_dirs[d] = nil
+        end
+    end
     return r
 end
 
@@ -547,6 +561,7 @@ function M.refresh_all()
 end
 
 function M.update_cwd_repo()
+    no_repo_dirs = {}
     local tab = vim.api.nvim_get_current_tabpage()
     local new = M.resolve(vim.fn.getcwd())
     local old