ci: add path filters to all workflows

[PythonWoods-Dev]

All four CI workflows now trigger only when relevant files change,
aligning with the path-filter strategy already used in the zenzic repo.

• ci.yml: docs/, i18n/, src/, static/, scripts/**,
  docusaurus.config.ts, sidebars.ts, package.json,
  package-lock.json, tsconfig.json, zenzic.toml
• codeql.yml: src/, scripts/
• npm-audit.yml: package.json, package-lock.json
• dependency-review.yml: package.json, package-lock.json

All workflows retain their schedule-based runs where applicable.
pull_request now also specifies branches: [main, release/**].

aligning with the path-filter strategy already used in the zenzic repo.

- ci.yml: docs/**, i18n/**, src/**, static/**, scripts/**,
          docusaurus.config.ts, sidebars.ts, package.json,
          package-lock.json, tsconfig.json, zenzic.toml
- codeql.yml: src/**, scripts/**
- npm-audit.yml: package.json, package-lock.json
- dependency-review.yml: package.json, package-lock.json

All workflows retain their schedule-based runs where applicable.
pull_request now also specifies branches: [main, release/**].