docs: encourage adding comments; fix nested IF/ELSIF indentation

- Update AGENTS.md to encourage comments instead of forbidding them
- Add docstrings to all public functions in src/ modules
- Add module headers and function comments to lua/scl/ modules
- Fix formatter to properly indent multi-line IF/ELSIF conditions
- Fix FB call detection to not match IF statements with parentheses

src/main.lua

@@ -154,6 +154,9 @@ end
 
 local handlers = {}
 
+--- Handle LSP initialize request
+--- @param params table Initialization parameters from client
+--- @return table Server capabilities and info
 function handlers.initialize(params)
 	return {
 		capabilities = capabilities,
@@ -161,8 +164,13 @@ function handlers.initialize(params)
 	}
 end
 
+--- Handle initialized notification (no response needed)
+--- @param params table Parameters (usually empty)
 function handlers.initialized(params) end
 
+--- Handle shutdown request
+--- @param params table Parameters (usually empty)
+--- @return nil
 function handlers.shutdown(params)
 	return nil
 end
@@ -206,10 +214,15 @@ local function find_project_root(start_path)
 	return nil
 end
 
+--- Handle exit notification - terminates the server
+--- @param params table Parameters (usually empty)
 function handlers.exit(params)
 	os.exit(0)
 end
 
+--- Handle textDocument/didOpen notification
+--- Parses document content, extracts symbols, and stores in documents cache
+--- @param params table Contains textDocument with uri, text, version
 function handlers.textDocument_didOpen(params)
 	local uri = params.textDocument.uri
 	local content = params.textDocument.text
@@ -247,6 +260,9 @@ function handlers.textDocument_didOpen(params)
 	}
 end
 
+--- Handle textDocument/didChange notification
+--- Re-parses document content after edits
+--- @param params table Contains textDocument with uri and contentChanges array
 function handlers.textDocument_didChange(params)
 	local uri = params.textDocument.uri
 	local content = params.contentChanges[1].text
@@ -285,11 +301,18 @@ function handlers.textDocument_didChange(params)
 	clear_symbol_cache()
 end
 
+--- Handle textDocument/didClose notification
+--- Removes document from cache
+--- @param params table Contains textDocument with uri
 function handlers.textDocument_didClose(params)
 	documents[params.textDocument.uri] = nil
 	clear_symbol_cache()
 end
 
+--- Handle textDocument/hover request
+--- Provides hover information for variables, types, and built-in instructions
+--- @param params table Contains textDocument with uri and position
+--- @return table|nil Hover result with contents and range, or nil
 function handlers.textDocument_hover(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -699,6 +722,10 @@ function handlers.textDocument_hover(params)
 	return nil
 end
 
+--- Handle textDocument/completion request
+--- Provides completion items based on context (VAR section, member access, etc.)
+--- @param params table Contains textDocument with uri and position
+--- @return table Completion list with items array
 function handlers.textDocument_completion(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -879,6 +906,10 @@ function handlers.textDocument_completion(params)
 	return { isIncomplete = false, items = items }
 end
 
+--- Handle textDocument/definition request
+--- Finds definition location for symbol at position
+--- @param params table Contains textDocument with uri and position
+--- @return table|nil Location with uri and range, or nil
 function handlers.textDocument_definition(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -921,6 +952,10 @@ function handlers.textDocument_definition(params)
 	return nil
 end
 
+--- Handle textDocument/declaration request
+--- Finds declaration locations for symbol at position across workspace
+--- @param params table Contains textDocument with uri and position
+--- @return table|nil Array of locations, or nil
 function handlers.textDocument_declaration(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1141,6 +1176,10 @@ function handlers.textDocument_declaration(params)
 	return nil
 end
 
+--- Handle textDocument/references request
+--- Finds all references to symbol at position in current document
+--- @param params table Contains textDocument with uri and position
+--- @return table|nil Array of reference locations, or nil
 function handlers.textDocument_references(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1202,6 +1241,10 @@ function handlers.textDocument_references(params)
 	return nil
 end
 
+--- Handle textDocument/documentSymbol request
+--- Returns all symbols in document for outline/navigation
+--- @param params table Contains textDocument with uri
+--- @return table Array of DocumentSymbol objects
 function handlers.textDocument_documentSymbol(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1286,6 +1329,10 @@ function handlers.textDocument_documentSymbol(params)
 	return symbols
 end
 
+--- Handle textDocument/diagnostic request
+--- Validates document and returns diagnostics
+--- @param params table Contains textDocument with uri
+--- @return table Diagnostic report with items array
 function handlers.textDocument_diagnostic(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1302,6 +1349,10 @@ function handlers.textDocument_diagnostic(params)
 	return { items = diag_results }
 end
 
+--- Handle textDocument/semanticTokens/full request
+--- Returns semantic tokens for syntax highlighting (currently disabled)
+--- @param params table Contains textDocument with uri
+--- @return table Semantic tokens with data array
 function handlers.textDocument_semanticTokensFull(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1399,6 +1450,10 @@ function handlers.textDocument_semanticTokensFull(params)
 	return { data = tokens }
 end
 
+--- Handle textDocument/semanticTokens/range request
+--- Returns semantic tokens for a range (delegates to full)
+--- @param params table Contains textDocument with uri and range
+--- @return table Semantic tokens with data array
 function handlers.textDocument_semanticTokensRange(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1412,6 +1467,10 @@ end
 handlers["textDocument_semanticTokens_full"] = handlers.textDocument_semanticTokensFull
 handlers["textDocument_semanticTokens_range"] = handlers.textDocument_semanticTokensRange
 
+--- Handle textDocument/inlayHint request
+--- Provides inlay hints for variable types in VAR sections
+--- @param params table Contains textDocument with uri and range
+--- @return table Array of InlayHint objects
 function handlers.textDocument_inlayHint(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]
@@ -1449,6 +1508,10 @@ function handlers.textDocument_inlayHint(params)
 	return hints
 end
 
+--- Handle workspace/symbol request
+--- Searches workspace for symbols matching query
+--- @param params table Contains query string and optional maxResults
+--- @return table Array of SymbolInformation objects
 function handlers.workspace_symbol(params)
 	local query = params.query or ""
 	local max_results = params.maxResults or 50
@@ -1586,6 +1649,10 @@ function handlers.workspace_symbol(params)
 	return final_results
 end
 
+--- Handle textDocument/formatting request
+--- Formats entire document using SCL formatter
+--- @param params table Contains textDocument with uri and options
+--- @return table|nil Array of TextEdit objects, or nil
 function handlers.textDocument_formatting(params)
 	local uri = params.textDocument.uri
 	local doc = documents[uri]