chore: pinned pre-commit hooks are out of date

[github-actions]

The weekly check found newer pinned revisions for pre-commit hooks that Dependabot cannot bump (it has no pre-commit ecosystem).

Run pre-commit autoupdate locally, review, and commit the result.

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 25b9769..d0cd13e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -28,7 +28,7 @@ repos:
   # Repo hygiene — fast, language-agnostic sanity checks.
   # ---------------------------------------------------------------------------
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
+    rev: v6.0.0
     hooks:
       - id: trailing-whitespace
         # Markdown trailing whitespace is meaningful (two spaces = hard break).
@@ -48,7 +48,7 @@ repos:
   # touches prompts/context must never leak keys/tokens/credentials).
   # ---------------------------------------------------------------------------
   - repo: https://github.com/gitleaks/gitleaks
-    rev: v8.21.2
+    rev: v8.30.0
     hooks:
       - id: gitleaks
 
@@ -79,7 +79,7 @@ repos:
   # bundles its own Node tool, so it needs NO repo dependencies.
   # ---------------------------------------------------------------------------
   - repo: https://github.com/DavidAnson/markdownlint-cli2
-    rev: v0.22.1
+    rev: v0.23.2
     hooks:
       - id: markdownlint-cli2
         exclude: "(^|/)node_modules/"
@@ -88,7 +88,7 @@ repos:
   # Conventional Commits — enforced on the commit message (commit-msg hook).
   # ---------------------------------------------------------------------------
   - repo: https://github.com/compilerla/conventional-pre-commit
-    rev: v3.6.0
+    rev: v4.4.0
     hooks:
       - id: conventional-pre-commit
         stages: [commit-msg]