fix: DB completion path parsing, array-of-UDT resolution, blink source registration

- Fix path extraction pattern (missing closing quote, extra capture group)
- Add Array[..] of "UdtName" detection for nested member resolution
- Remove vim.schedule_wrap from DB member callback (causes blink.cmp timeout)
- Add built-in instruction parameter fallback (IEC_TIMER IN/PT/Q/ET)
- Ensure DB cache is populated on demand in completion source
- Make try_register() succeed without cmp.add_source_provider API
- docs: add blink.cmp source config steps to installation guide

lua/tia_lsp/init.lua

@@ -177,17 +177,18 @@ function M.setup_syntax(opts)
 	if opts.cmp then
 		local function try_register()
 			local cmp_ok, cmp = pcall(require, "blink.cmp")
-			local blink_source_ok, blink_source = pcall(require, "tia.blink_cmp_source")
-			if cmp_ok and cmp and cmp.add_source_provider and blink_source_ok then
-				local source_config = {
-					name = "scl",
-					provider = blink_source,
-					score_offset = 100,
-				}
-				pcall(cmp.add_source_provider, "scl", source_config)
-				pcall(cmp.add_filetype_source, "scl", "scl")
-
-				vim.notify("SCL: blink.cmp source registered", vim.log.levels.INFO)
+			local blink_source_ok = pcall(require, "tia.blink_cmp_source")
+			if cmp_ok and cmp and blink_source_ok then
+				if cmp.add_source_provider then
+					local blink_source = require("tia.blink_cmp_source")
+					local source_config = {
+						name = "scl",
+						provider = blink_source,
+						score_offset = 100,
+					}
+					pcall(cmp.add_source_provider, "scl", source_config)
+					pcall(cmp.add_filetype_source, "scl", "scl")
+				end
 				return true
 			end
 			return false