refactor(rainbow-delims): separate concerns with condition API

Move parser health checks (nil guard, error count) to rainbow-delimiters
native `condition` API. Simplify `init_strategy` to only select
global/local based on line count. pcall handles both nvim 0.11 (throws)
and 0.12+ (returns nil) get_parser behavior.

Author: charliie-dev

lua/modules/configs/editor/rainbow_delims.lua

@@ -1,26 +1,13 @@
 return function()
+	local rd = require("rainbow-delimiters")
+
 	---@param threshold number @Use global strategy if nr of lines exceeds this value
 	local function init_strategy(threshold)
 		return function()
-			-- Disable on very large files
-			local line_count = vim.api.nvim_buf_line_count(0)
-			if line_count > 15000 then
-				return nil
-			end
-
-			-- Disable on parser error
-			local errors = 200
-			vim.treesitter.get_parser():for_each_tree(function(lt)
-				if lt:root():has_error() and errors >= 0 then
-					errors = errors - 1
-				end
-			end)
-			if errors < 0 then
-				return nil
+			if vim.api.nvim_buf_line_count(0) > threshold then
+				return rd.strategy["global"]
 			end
-
-			return line_count > threshold and require("rainbow-delimiters").strategy["global"]
-				or require("rainbow-delimiters").strategy["local"]
+			return rd.strategy["local"]
 		end
 	end
 
@@ -33,6 +20,24 @@ return function()
 			vimdoc = init_strategy(300),
 			vim = init_strategy(300),
 		},
+		---@param buf number
+		condition = function(buf)
+			if vim.api.nvim_buf_line_count(buf) > 15000 then
+				return false
+			end
+			-- pcall handles both nvim 0.11 (throws) and 0.12+ (returns nil)
+			local ok, parser = pcall(vim.treesitter.get_parser, buf)
+			if not ok or not parser then
+				return false
+			end
+			local errors = 200
+			parser:for_each_tree(function(lt)
+				if lt:root():has_error() and errors >= 0 then
+					errors = errors - 1
+				end
+			end)
+			return errors >= 0
+		end,
 		query = {
 			[""] = "rainbow-delimiters",
 			latex = "rainbow-blocks",