chore: migrate from super-linter to flint v2 (#1988)

## Summary

- Replaces `lint:super-linter`, `lint:links`, and `lint:renovate-deps`
tasks with a single `flint run` invocation
- Adds `google-java-format` via `github:google/google-java-format` and
standard native lint tools through `mise`
- Creates `.github/config/flint.toml` with path exclusions
(`docs/themes/`, `src/main/generated/`, `mvnw`, `simpleclient-archive/`)
and migrates `RENOVATE_TRACKED_DEPS_EXCLUDE` to `[checks.renovate-deps]
exclude_managers`
- Removes Spotless from the branch; flint does not replace Maven
Checkstyle
- Updates GitHub Actions to `mise v2026.4.16` so `raw_args = true` is
supported in the flint-backed `lint` task

## Test plan

- [ ] CI jobs pass
- [x] `mise run lint`
- [x] `mise run lint:fix`
- [x] `flint run --fix renovate-deps` reflected in
`.github/renovate-tracked-deps.json`

---------

Signed-off-by: Gregor Zeitlinger <gregor.zeitlinger@grafana.com>

Author: zeitlinger

.codespellrc

@@ -1,5 +1,6 @@
 [codespell]
-# Ignore words that are valid technical terms:
-# - vertx: Vert.x reactive framework
-# - errorprone: Error Prone static analysis tool
-ignore-words-list = vertx,errorprone
+# nd: legitimate variable name in quantile algorithms
+# atmost: AssertJ atMost() matcher
+# re-use: hyphenated form used in comments
+# errorprone: Google ErrorProne tool name
+ignore-words-list = nd,atmost,re-use,errorprone

.editorconfig

@@ -7,7 +7,7 @@ indent_size = 2
 [{version-rules.xml,maven-wrapper.properties,checkstyle.xml,docker-compose.yaml,docker-compose.yml,Dockerfile,example_target_info.json,mise.toml,mvnm,mvnw.cmd,generate-protobuf.sh,.gitleaksignore,prometheus.properties}]
 max_line_length = 200
 
-[{grafana-dashboard-*.json,.editorconfig,super-linter.env,lychee.toml,renovate.json5}]
+[{grafana-dashboard-*.json,.editorconfig,super-linter.env,lychee.toml,renovate.json5,CODE_OF_CONDUCT.md}]
 max_line_length = 300
 
 [pom.xml]
@@ -18,5 +18,5 @@ max_line_length = 210
 indent_size = 4
 max_line_length = 120
 
-[{.mise/tasks/build-release.sh,.github/workflows/multi-version-test.yml}]
-max_line_length = 200
+[{.mise/tasks/build-release.sh,.github/workflows/*.yml}]
+max_line_length = 300

.github/config/.editorconfig-checker.json

@@ -0,0 +1,4 @@
+{
+  "_comment": "Java files are handled by flint, so editorconfig-checker ignores them.",
+  "Exclude": [".*\\.java$"]
+}

.github/config/flint.toml

@@ -0,0 +1,14 @@
+[settings]
+# These paths are generated, vendored, or handled by other checks.
+exclude = [
+    "CHANGELOG.md",
+    "**/src/main/generated/**",
+    "docs/themes/**",
+    "mvnw",
+    "simpleclient-archive/**",
+]
+
+[checks.renovate-deps]
+# This inventory is regenerated from the files flint still inspects, so
+# super-linter-era entries drop out when they are excluded or no longer used.
+exclude_managers = ["github-actions", "github-runners", "maven"]