feat(json,yaml): add tree-sitter modes, formatting, and jq integration

New prog-json module: json-ts-mode with jq formatting (C-; f) and
jq-interactively (C-c C-q). Upgraded prog-yaml to yaml-ts-mode with
prettier formatting. Both use treesit-auto for grammar management.
Includes 18 new tests (10 JSON, 8 YAML), 185/185 passing.

1 files changed, 37 insertions, 7 deletions

diff --git a/modules/prog-yaml.el b/modules/prog-yaml.el
index 1a970313..8411f04c 100644
--- a/modules/prog-yaml.el
+++ b/modules/prog-yaml.el
@@ -2,17 +2,47 @@
 ;; author: Craig Jennings <c@cjennings.net>
 
 ;;; Commentary:
+;; YAML editing with tree-sitter highlighting and one-key formatting.
+;;
+;; Features:
+;;   - Tree-sitter: Syntax highlighting and structural navigation
+;;   - Formatting: Normalize indentation and style via C-; f
+;;
+;; Workflow:
+;;   1. Open .yml/.yaml file → yaml-ts-mode with tree-sitter highlighting
+;;   2. C-; f → Format buffer with prettier
 
 ;;; Code:
 
-(use-package yaml-mode
-  :defer .5
-  :commands (yaml-mode)
-  :config
-  (add-to-list 'auto-mode-alist '("\\.yml\\'" . yaml-mode))
-  (add-to-list 'auto-mode-alist '("\\.yaml\\'" . yaml-mode)))
+;; -------------------------------- YAML Mode ----------------------------------
+;; tree-sitter mode for YAML files (built-in, Emacs 29+)
+;; NOTE: No :mode directive — treesit-auto (in prog-general.el) handles
+;; the auto-mode-alist mapping and auto-installs the grammar on first use.
 
-(add-hook 'yaml-mode-hook ' flycheck-mode-hook)
+(use-package yaml-ts-mode
+  :ensure nil
+  :defer t)
+
+;; -------------------------------- Formatting ---------------------------------
+;; normalize indentation and style, bound to standard format key
+
+(defun cj/yaml-format-buffer ()
+  "Format the current YAML buffer with prettier.
+Preserves point position as closely as possible."
+  (interactive)
+  (if (executable-find "prettier")
+      (let ((point (point)))
+        (shell-command-on-region (point-min) (point-max)
+                                "prettier --parser yaml" nil t)
+        (goto-char (min point (point-max))))
+    (user-error "prettier not found; install with: npm install -g prettier")))
+
+(defun cj/yaml-setup ()
+  "Set up YAML buffer keybindings and linting."
+  (local-set-key (kbd "C-; f") #'cj/yaml-format-buffer)
+  (flycheck-mode 1))
+
+(add-hook 'yaml-ts-mode-hook #'cj/yaml-setup)
 
 (provide 'prog-yaml)
 ;;; prog-yaml.el ends here