feat(cli): output formats, GL034-GL041 lint rules, include inputs and cache

Bundles three patch releases (v0.2.16–v0.2.18):

v0.2.18 — output formats (--format flag on glint check):
- json: stable JSON report (schema_version: 1, findings array, summary)
- sarif: SARIF 2.1.0 for GitHub Code Scanning / GitLab SAST
- junit: JUnit XML for CI test-report artifacts (artifacts:reports:junit)
- github: GitHub Actions ::error:: / ::warning:: annotation lines
- Unknown --format value exits 2 with a helpful error message
- Summary line routed to stderr in structured formats; context suppressed

v0.2.17 — include resolution improvements:
- Recursive include depth capped at 100 (matches GitLab's own limit)
- project: and component: includes tracked in visited set (cycle detection)
- $[[ inputs.KEY ]] / $[[ inputs.KEY | default(…) ]] substituted from with:
- --cache-dir: persist fetched remote templates to disk (SHA-256 keyed)
- --offline: serve from cache only; defaults to ~/.cache/glint

v0.2.16 — new lint rules (GL034–GL041):
- GL034: services map form requires name; alias must be valid DNS label
- GL035: rules:changes / rules:exists absolute path detection
- GL036: timeout format validation (job-level + default.timeout)
- GL037: id_tokens entries must have an aud key
- GL038: secrets entries must declare a provider (vault / gcp / azure)
- GL039: pages: keyword + artifacts.paths consistency
- GL040: duplicate stage names in stages: list
- GL041: cache.key.files must be exact paths, not globs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Taskfile.yml

@@ -83,12 +83,24 @@ tasks:
         ignore_error: false
       - cmd: ./{{.BINARY}} check testdata/dead_rules.yml
         ignore_error: false
+      - cmd: ./{{.BINARY}} check testdata/new_rules_valid.yml
+        ignore_error: false
+      - cmd: ./{{.BINARY}} check testdata/new_rules_invalid.yml
+        ignore_error: true
       - cmd: ./{{.BINARY}} check testdata/samba/.gitlab-ci.yml
         ignore_error: false
       - cmd: ./{{.BINARY}} check testdata/samba/.gitlab-ci-coverage.yml
         ignore_error: false
       - cmd: ./{{.BINARY}} check testdata/samba/.gitlab-ci-private.yml
         ignore_error: false
+      - cmd: ./{{.BINARY}} check --format json testdata/valid.yml
+        ignore_error: false
+      - cmd: ./{{.BINARY}} check --format sarif testdata/valid.yml
+        ignore_error: false
+      - cmd: ./{{.BINARY}} check --format junit testdata/valid.yml
+        ignore_error: false
+      - cmd: ./{{.BINARY}} check --format github testdata/invalid.yml
+        ignore_error: true
 
   lint-go:
     desc: Run go vet on all packages