🔧 Migrate lefthook config to v2 schema

The previous config was a hybrid of v1 (jobs: array) and v1
(top-level commands: block) that no longer validates under
lefthook 2.x. lefthook 2.0.0's schema has top-level 'commands:'
set to 'false'; the v1 jobs: array form still works, but the
orphan named-commands block at the top was silently invalid
(caught by 'lefthook validate').

Migrate to the v2-native 'commands:' (named) form under the hook:

  pre-commit:
    parallel: true
    commands:
      oxlint:
        glob: ...
        run: npx oxlint {staged_files}
      ...

Changes:
- Add 'min_version: 2.0.0' to declare the v2 schema explicitly
- Replace pre-commit.jobs: array with pre-commit.commands: (named)
- Inline the glob on each command (was a top-level property on each
  job in v1)
- Remove the orphan top-level 'commands:' block — it was never
  referenced by any hook, and v2 forbids it
- Update project-specs.md: drop the dangling reference to the
  lefthook 'commands:' block (it was the dead top-level one);
  describe the v2 commands: form

Verified:
- 'lefthook validate' reports 'All good'
- 'lefthook run pre-commit' executes all 5 hooks (oxlint, oxfmt,
  sort-package-json, typecheck, cspell); globs correctly skip hooks
  on non-matching files (e.g. lefthook.yml alone) and run them on
  TS/JS changes
- 'npm run check' exits 0
- 'lefthook dump' shows the normalized v2 config

lefthook.yml

@@ -1,29 +1,17 @@
+min_version: 2.0.0
+
 pre-commit:
     parallel: true
-    jobs:
-        - name: oxlint
-          glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
-          run: npx oxlint {staged_files}
-        - name: oxfmt
-          glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
-          run: npx oxfmt --check {staged_files}
-        - name: cspell
-          run: npx cspell {staged_files}
-        - name: sort-package-json
-          run: npx sort-package-json --check
-        - name: typecheck
-          run: npx tsc --noEmit
-
-commands:
-    typecheck:
-        run: npm run check:tsc
-    spell:
-        run: npm run check:cspell
-    sort:
-        run: npm run check:package
-    lint:
-        run: npm run check:oxlint
-    format:
-        run: npm run check:oxfmt
-    outdated:
-        run: npm run check:outdated
+    commands:
+        oxlint:
+            glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
+            run: npx oxlint {staged_files}
+        oxfmt:
+            glob: "*.{ts,tsx,js,jsx,mjs,cjs}"
+            run: npx oxfmt --check {staged_files}
+        cspell:
+            run: npx cspell {staged_files}
+        sort-package-json:
+            run: npx sort-package-json --check
+        typecheck:
+            run: npx tsc --noEmit