Add editor tooling configuration

clangd fallback flags, clang-format style, clang-tidy checks, and gitignore for the autotools-generated artifacts.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <[email protected]>

.gitignore

@@ -1,49 +1,50 @@
-# ---> C
-# Prerequisites
-*.d
+# Generated by autotools
+aclocal.m4
+autom4te.cache/
+build-aux/
+config.guess
+config.h.in
+config.log
+config.status
+config.sub
+configure
+configure.lineno
+depcomp
+install-sh
+ltmain.sh
+missing
+Makefile.in
 
-# Object files
+# Build artifacts
 *.o
+*.a
+*.lo
+*.la
+.deps/
+.libs/
+
+# Generic C artifacts (for experiments outside the autotools flow)
 *.ko
 *.obj
 *.elf
-
-# Linker output
 *.ilk
 *.map
 *.exp
-
-# Precompiled Headers
 *.gch
 *.pch
-
-# Libraries
 *.lib
-*.a
-*.la
-*.lo
-
-# Shared objects (inc. Windows DLLs)
 *.dll
 *.so
 *.so.*
 *.dylib
-
-# Executables
 *.exe
 *.out
 *.app
-*.i*86
-*.x86_64
 *.hex
-
-# Debug files
 *.dSYM/
 *.su
 *.idb
 *.pdb
-
-# Kernel Module Compile Results
 *.mod*
 *.cmd
 .tmp_versions/
@@ -52,3 +53,16 @@ Module.symvers
 Mkfile.old
 dkms.conf
 
+# Out-of-tree build dirs (the driver Makefile owns these)
+bin/release/*
+!bin/release/.gitkeep
+bin/debug/*
+!bin/debug/.gitkeep
+
+# LSP (generated by `make compile_commands`)
+compile_commands.json
+
+# Editor/agent caches
+.cache/
+.omo/
+*~