nvim: fix startup errors, add language + project-run support

Startup errors:
- catppuccin: the bufferline integration moved to catppuccin.special.bufferline
- lspconfig-extended: drop the removed LazyVim keymaps API for
  opts.servers["*"].keys, and move remove-workspace-folder to <leader>clR
  so it stops colliding with LspRestart on <leader>clr
- options: lazyvim_cmp = "blink" is not a valid value, it is "blink.cmp"

Language support (python, c/cpp, rust, zephyr, and the common ones) via
lazyvim.json extras: dap.core, clangd, cmake, docker, git, json, rust,
toml, yaml.

- lang/zephyr.lua: gated entirely on ZEPHYR_BASE / ZEPHYR_SDK_INSTALL_DIR /
  GNUARMEMB_TOOLCHAIN_PATH, returning {} when none are set, so it is inert
  on machines without Zephyr. Nothing is hardcoded: the clangd
  --query-driver globs are built from those vars, falling back to resolving
  the cross-gcc through exepath()+fs_realpath(). Adds devicetree/kconfig
  treesitter and filetypes (*.overlay, Kconfig.*, prj.conf, *_defconfig).
- clangd/config.yaml: strip the GCC-only flags Zephyr emits into
  compile_commands.json (-fno-printf-return-value, -mfp16-format=*, ...),
  which clang rejects as "Unknown argument". Remove only drops flags that
  are present, so it is a no-op for native builds. Takes a built Zephyr app
  from 15 diagnostics to 0, with CONFIG_* resolving into the generated
  autoconf.h.
- npm-servers.lua: npm is not installed here, so yaml/docker servers failed
  to install on every startup and to spawn on every matching file. Sets
  both enabled = false and mason = false for servers whose binary is
  missing from PATH and from mason/bin.

Project runner under <leader>R (<leader>r is refactoring), dispatching on
the detected project type -- zephyr, rust, python, cmake, make:

  Rr run project   Rb build   Rt test   RF build+flash   Rf run file
  Rk configure     Rc clean   Rs select target/board     Ri info

Zephyr boards are picked with vim.ui.select over `west boards`, cached per
scan and persisted per project root under stdpath("state"), never written
into the project. A build with no board set prompts first, then proceeds.
Detection walks up from the last real file buffer, tracked by an autocmd,
because a terminal opened by one of these verbs would otherwise become the
buffer detection ran from.

Also <leader>b1..b9/b0 jump to buffer N (ordinal, no longer skipping the
current one) and <leader>b<Left>/<Right> cycle.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01StGBghPW9Dm7z7uj2VNWHr

clangd/config.yaml

@@ -0,0 +1,26 @@
+# clangd user configuration.
+#
+# Cross-compiled embedded builds (Zephyr in particular) put GCC-only flags into
+# compile_commands.json. clangd is clang, does not recognise them, and reports
+# "Unknown argument: ..." on line 1 of every file in the project -- even though
+# the code itself is fine and all symbols resolve.
+#
+# Stripping them here, once, fixes every such project without needing a .clangd
+# file checked into each one. Remove only drops a flag if it is actually
+# present, so this is inert for native builds.
+#
+# If a new one shows up for another target (RISC-V, Xtensa ...), the message
+# names it exactly -- add it to the list below.
+
+CompileFlags:
+  Remove:
+    # --- seen in Zephyr / arm-none-eabi builds ---
+    - -fno-printf-return-value
+    - -fno-reorder-functions
+    - -fno-defer-pop
+    - -fconserve-stack
+    - -fno-freestanding
+    - -mfp16-format=*
+    - -mno-fdpic
+    # GCC tuning params clang has no equivalent for
+    - --param=*