refactor: revert canola namespace to oil and remove vim.g config (#120)

* refactor: revert module namespace from canola back to oil

Problem: the canola rename creates unnecessary friction for users
migrating from stevearc/oil.nvim — every `require('oil')` call and
config reference must change.

Solution: revert all module paths, URL schemes, autocmd groups,
highlight groups, and filetype names back to `oil`. The repo stays
`canola.nvim` for identity; the code is a drop-in replacement.

* refactor: remove `vim.g.oil` declarative config

Problem: the `vim.g.oil` configuration path was added prematurely.
It adds a second config entrypoint before the plugin has stabilized
enough to justify it.

Solution: remove `vim.g.oil` support from `plugin/oil.lua`,
`config.setup()`, docs, and tests. Users configure via
`require("oil").setup({})`.

lua/oil/lsp/workspace.lua

@@ -0,0 +1,351 @@
+local fs = require('oil.fs')
+local ms = require('vim.lsp.protocol').Methods
+if vim.fn.has('nvim-0.10') == 0 then
+  ms = {
+    workspace_willCreateFiles = 'workspace/willCreateFiles',
+    workspace_didCreateFiles = 'workspace/didCreateFiles',
+    workspace_willDeleteFiles = 'workspace/willDeleteFiles',
+    workspace_didDeleteFiles = 'workspace/didDeleteFiles',
+    workspace_willRenameFiles = 'workspace/willRenameFiles',
+    workspace_didRenameFiles = 'workspace/didRenameFiles',
+  }
+end
+
+local M = {}
+
+---@param method string
+---@return vim.lsp.Client[]
+local function get_clients(method)
+  if vim.fn.has('nvim-0.10') == 1 then
+    return vim.lsp.get_clients({ method = method })
+  else
+    ---@diagnostic disable-next-line: deprecated
+    local clients = vim.lsp.get_active_clients()
+    return vim.tbl_filter(function(client)
+      return client.supports_method(method)
+    end, clients)
+  end
+end
+
+---@param glob string|vim.lpeg.Pattern
+---@param path string
+---@return boolean
+local function match_glob(glob, path)
+  -- nvim-0.10 will have vim.glob.to_lpeg, so this will be a LPeg pattern
+  if type(glob) ~= 'string' then
+    return glob:match(path) ~= nil
+  end
+
+  -- older versions fall back to glob2regpat
+  local pat = vim.fn.glob2regpat(glob)
+  local ignorecase = vim.o.ignorecase
+  vim.o.ignorecase = false
+  local ok, match = pcall(vim.fn.match, path, pat)
+  vim.o.ignorecase = ignorecase
+  if not ok then
+    error(match)
+  end
+  return match >= 0
+end
+
+---@param client vim.lsp.Client
+---@param filters nil|lsp.FileOperationFilter[]
+---@param paths string[]
+---@return nil|string[]
+local function get_matching_paths(client, filters, paths)
+  if not filters then
+    return nil
+  end
+
+  local match_fns = {}
+  for _, filter in ipairs(filters) do
+    if filter.scheme == nil or filter.scheme == 'file' then
+      local pattern = filter.pattern
+      local glob = pattern.glob
+      local ignore_case = pattern.options and pattern.options.ignoreCase
+      if ignore_case then
+        glob = glob:lower()
+      end
+
+      -- Some language servers use forward slashes as path separators on Windows (LuaLS)
+      -- We no longer need this after 0.12: https://github.com/neovim/neovim/commit/322a6d305d088420b23071c227af07b7c1beb41a
+      if vim.fn.has('nvim-0.12') == 0 and fs.is_windows then
+        glob = glob:gsub('/', '\\')
+      end
+
+      ---@type string|vim.lpeg.Pattern
+      local glob_to_match = glob
+      if vim.glob and vim.glob.to_lpeg then
+        glob = glob:gsub('{(.-)}', function(s)
+          local patterns = vim.split(s, ',')
+          local filtered = {}
+          for _, pat in ipairs(patterns) do
+            if pat ~= '' then
+              table.insert(filtered, pat)
+            end
+          end
+          if #filtered == 0 then
+            return ''
+          end
+          -- HACK around https://github.com/neovim/neovim/issues/28931
+          -- find alternations and sort them by length to try to match the longest first
+          if vim.fn.has('nvim-0.11') == 0 then
+            table.sort(filtered, function(a, b)
+              return a:len() > b:len()
+            end)
+          end
+          return '{' .. table.concat(filtered, ',') .. '}'
+        end)
+
+        glob_to_match = vim.glob.to_lpeg(glob)
+      end
+      local matches = pattern.matches
+      table.insert(match_fns, function(path)
+        local is_dir = vim.fn.isdirectory(path) == 1
+        if matches and ((matches == 'file' and is_dir) or (matches == 'folder' and not is_dir)) then
+          return false
+        end
+
+        if ignore_case then
+          path = path:lower()
+        end
+        return match_glob(glob_to_match, path)
+      end)
+    end
+  end
+  local function match_any_pattern(workspace, path)
+    local relative_path = path:sub(workspace:len() + 2)
+    for _, match_fn in ipairs(match_fns) do
+      -- The glob pattern might be relative to workspace OR absolute
+      if match_fn(relative_path) or match_fn(path) then
+        return true
+      end
+    end
+    return false
+  end
+
+  local workspace_folders = vim.tbl_map(function(folder)
+    return vim.uri_to_fname(folder.uri)
+  end, client.workspace_folders or {})
+  local function get_matching_workspace(path)
+    for _, workspace in ipairs(workspace_folders) do
+      if fs.is_subpath(workspace, path) then
+        return workspace
+      end
+    end
+  end
+
+  local ret = {}
+  for _, path in ipairs(paths) do
+    local workspace = get_matching_workspace(path)
+    if workspace and match_any_pattern(workspace, path) then
+      table.insert(ret, path)
+    end
+  end
+  if vim.tbl_isempty(ret) then
+    return nil
+  else
+    return ret
+  end
+end
+
+---@param method string The method to call
+---@param capability_name string The name of the fileOperations server capability
+---@param files string[] The files and folders that will be created
+---@param options table|nil
+---@return nil|{edit: lsp.WorkspaceEdit, offset_encoding: string}[]
+---@return nil|string|lsp.ResponseError err
+local function will_file_operation(method, capability_name, files, options)
+  options = options or {}
+  local clients = get_clients(method)
+
+  local edits = {}
+  for _, client in ipairs(clients) do
+    local filters = vim.tbl_get(
+      client.server_capabilities,
+      'workspace',
+      'fileOperations',
+      capability_name,
+      'filters'
+    )
+    local matching_files = get_matching_paths(client, filters, files)
+    if matching_files then
+      local params = {
+        files = vim.tbl_map(function(file)
+          return {
+            uri = vim.uri_from_fname(file),
+          }
+        end, matching_files),
+      }
+      local result, err
+      if vim.fn.has('nvim-0.11') == 1 then
+        result, err = client:request_sync(method, params, options.timeout_ms or 1000, 0)
+      else
+        ---@diagnostic disable-next-line: param-type-mismatch
+        result, err = client.request_sync(method, params, options.timeout_ms or 1000, 0)
+      end
+      if result and result.result then
+        if options.apply_edits ~= false then
+          vim.lsp.util.apply_workspace_edit(result.result, client.offset_encoding)
+        end
+        table.insert(edits, { edit = result.result, offset_encoding = client.offset_encoding })
+      else
+        return nil, err or result and result.err
+      end
+    end
+  end
+  return edits
+end
+
+---@param method string The method to call
+---@param capability_name string The name of the fileOperations server capability
+---@param files string[] The files and folders that will be created
+local function did_file_operation(method, capability_name, files)
+  local clients = get_clients(method)
+  for _, client in ipairs(clients) do
+    local filters = vim.tbl_get(
+      client.server_capabilities,
+      'workspace',
+      'fileOperations',
+      capability_name,
+      'filters'
+    )
+    local matching_files = get_matching_paths(client, filters, files)
+    if matching_files then
+      local params = {
+        files = vim.tbl_map(function(file)
+          return {
+            uri = vim.uri_from_fname(file),
+          }
+        end, matching_files),
+      }
+      if vim.fn.has('nvim-0.11') == 1 then
+        client:notify(method, params)
+      else
+        ---@diagnostic disable-next-line: param-type-mismatch
+        client.notify(method, params)
+      end
+    end
+  end
+end
+
+--- Notify the server that the client is about to create files.
+---@param files string[] The files and folders that will be created
+---@param options table|nil Optional table which holds the following optional fields:
+---    - timeout_ms (integer|nil, default 1000):
+---        Time in milliseconds to block for rename requests.
+---    - apply_edits (boolean|nil, default true):
+---        Apply any workspace edits from these file operations.
+---@return nil|{edit: lsp.WorkspaceEdit, offset_encoding: string}[]
+---@return nil|string|lsp.ResponseError err
+function M.will_create_files(files, options)
+  return will_file_operation(ms.workspace_willCreateFiles, 'willCreate', files, options)
+end
+
+--- Notify the server that files were created from within the client.
+---@param files string[] The files and folders that will be created
+function M.did_create_files(files)
+  did_file_operation(ms.workspace_didCreateFiles, 'didCreate', files)
+end
+
+--- Notify the server that the client is about to delete files.
+---@param files string[] The files and folders that will be deleted
+---@param options table|nil Optional table which holds the following optional fields:
+---    - timeout_ms (integer|nil, default 1000):
+---        Time in milliseconds to block for rename requests.
+---    - apply_edits (boolean|nil, default true):
+---        Apply any workspace edits from these file operations.
+---@return nil|{edit: lsp.WorkspaceEdit, offset_encoding: string}[]
+---@return nil|string|lsp.ResponseError err
+function M.will_delete_files(files, options)
+  return will_file_operation(ms.workspace_willDeleteFiles, 'willDelete', files, options)
+end
+
+--- Notify the server that files were deleted from within the client.
+---@param files string[] The files and folders that were deleted
+function M.did_delete_files(files)
+  did_file_operation(ms.workspace_didDeleteFiles, 'didDelete', files)
+end
+
+--- Notify the server that the client is about to rename files.
+---@param files table<string, string> Mapping of old_path -> new_path
+---@param options table|nil Optional table which holds the following optional fields:
+---    - timeout_ms (integer|nil, default 1000):
+---        Time in milliseconds to block for rename requests.
+---    - apply_edits (boolean|nil, default true):
+---        Apply any workspace edits from these file operations.
+---@return nil|{edit: lsp.WorkspaceEdit, offset_encoding: string}[]
+---@return nil|string|lsp.ResponseError err
+function M.will_rename_files(files, options)
+  options = options or {}
+  local clients = get_clients(ms.workspace_willRenameFiles)
+
+  local edits = {}
+  for _, client in ipairs(clients) do
+    local filters = vim.tbl_get(
+      client.server_capabilities,
+      'workspace',
+      'fileOperations',
+      'willRename',
+      'filters'
+    )
+    local matching_files = get_matching_paths(client, filters, vim.tbl_keys(files))
+    if matching_files then
+      local params = {
+        files = vim.tbl_map(function(src_file)
+          return {
+            oldUri = vim.uri_from_fname(src_file),
+            newUri = vim.uri_from_fname(files[src_file]),
+          }
+        end, matching_files),
+      }
+      local result, err
+      if vim.fn.has('nvim-0.11') == 1 then
+        result, err =
+          client:request_sync(ms.workspace_willRenameFiles, params, options.timeout_ms or 1000, 0)
+      else
+        result, err =
+          ---@diagnostic disable-next-line: param-type-mismatch
+          client.request_sync(ms.workspace_willRenameFiles, params, options.timeout_ms or 1000, 0)
+      end
+      if result and result.result then
+        if options.apply_edits ~= false then
+          vim.lsp.util.apply_workspace_edit(result.result, client.offset_encoding)
+        end
+        table.insert(edits, { edit = result.result, offset_encoding = client.offset_encoding })
+      else
+        return nil, err or result and result.err
+      end
+    end
+  end
+  return edits
+end
+
+--- Notify the server that files were renamed from within the client.
+---@param files table<string, string> Mapping of old_path -> new_path
+function M.did_rename_files(files)
+  local clients = get_clients(ms.workspace_didRenameFiles)
+  for _, client in ipairs(clients) do
+    local filters =
+      vim.tbl_get(client.server_capabilities, 'workspace', 'fileOperations', 'didRename', 'filters')
+    local matching_files = get_matching_paths(client, filters, vim.tbl_keys(files))
+    if matching_files then
+      local params = {
+        files = vim.tbl_map(function(src_file)
+          return {
+            oldUri = vim.uri_from_fname(src_file),
+            newUri = vim.uri_from_fname(files[src_file]),
+          }
+        end, matching_files),
+      }
+      if vim.fn.has('nvim-0.11') == 1 then
+        client:notify(ms.workspace_didRenameFiles, params)
+      else
+        ---@diagnostic disable-next-line: param-type-mismatch
+        client.notify(ms.workspace_didRenameFiles, params)
+      end
+    end
+  end
+end
+
+return M