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>

internal/linter/rules.go

@@ -118,4 +118,29 @@ const (
 	// GL033: every rule in a job's rules: block has when: never, so the job
 	// can never be included in any pipeline run.
 	RuleDeadRules = "GL033"
+
+	// GL034: services: map form is missing 'name', or 'alias' is not a valid DNS label.
+	RuleInvalidService = "GL034"
+
+	// GL035: rules:changes or rules:exists contains an absolute path (starts with /);
+	// GitLab CI paths are relative to the repository root and absolute paths never match.
+	RuleAbsoluteGlobPath = "GL035"
+
+	// GL036: timeout: is not a valid GitLab CI duration string (e.g. '1h 30m', '90 minutes').
+	RuleInvalidTimeout = "GL036"
+
+	// GL037: id_tokens: entry is missing the required 'aud' key.
+	RuleInvalidIDToken = "GL037"
+
+	// GL038: secrets: entry is missing a provider key (vault, gcp_secret_manager, or azure_key_vault).
+	RuleInvalidSecret = "GL038"
+
+	// GL039: a job has the pages: keyword but artifacts.paths does not include the publish directory.
+	RulePagesPublish = "GL039"
+
+	// GL040: a stage name appears more than once in stages:; GitLab silently merges duplicates.
+	RuleDuplicateStage = "GL040"
+
+	// GL041: cache.key.files contains a glob pattern; it must be a list of exact file paths.
+	RuleInvalidCacheKeyFiles = "GL041"
 )