chore(renovate): surface release age and changelogs, without gating on them

Three gaps in the Renovate setup, all about having enough information in
front of you at review time:

- The PR table had no Age/Adoption/Passing/Confidence columns. Those are
  Mend's Merge Confidence badges, which self-hosted Renovate only emits
  behind the `mergeConfidence:all-badges` preset. No credentials involved
  — Renovate embeds badge URLs and the browser resolves them on view.
- Release notes came back empty. We run against Gitea, but the packages
  are *released* on GitHub, so changelog lookups were going out
  unauthenticated against a 60/h limit. A scopeless read-only PAT
  (GITHUB_COM_TOKEN secret) lifts that.
- Nothing expressed how settled a release is. Cooling-off is now scaled
  by blast radius: 30 days major, 20 minor, 10 patch/digest.

The age tiers are deliberately advisory. Renovate's default
`internalChecksFilter: strict` would suppress the PR outright until the
version aged in; "none" opens it at the highest version immediately and
leaves a pending stability check behind, so merging ahead of the window
stays a decision rather than a wait.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

renovate.json5

@@ -5,6 +5,12 @@
     "config:recommended",
     // chore(deps): … — match the repo's conventional-commit style.
     ":semanticCommits",
+    // Adds the Age / Adoption / Passing / Confidence columns to the PR table
+    // (Mend's Merge Confidence badges; free, no token — Renovate only embeds
+    // the badge URLs and the browser loads them when the PR is viewed).
+    // Covers the maven datasource, i.e. everything in libs.versions.toml;
+    // the github-actions datasource has no badges, so those PRs stay plain.
+    "mergeConfidence:all-badges",
   ],
 
   // No automerge: a dependency bump goes through the same review (and, for
@@ -15,6 +21,16 @@
 
   // One reviewable surface; the dashboard issue lists everything pending.
   dependencyDashboard: true,
+
+  // The cooling-off periods below are advisory, not a gate: "none" turns off
+  // filtering on the minimumReleaseAge check, so the PR is opened at the
+  // highest version straight away and merging early stays a judgement call.
+  // (Renovate's default here is "strict", which suppresses the PR entirely
+  // until the release has aged in.) A still-young release carries a pending
+  // `renovate/stability-days` check so it's visible which side of the line
+  // it's on; with automerge off, nothing acts on that check by itself.
+  internalChecksFilter: "none",
+
   labels: ["dependencies"],
   prConcurrentLimit: 5,
   prHourlyLimit: 0,
@@ -30,6 +46,21 @@
   },
 
   packageRules: [
+    // Cooling-off period, scaled by blast radius: how long a release should
+    // have been out (and un-yanked, un-hotfixed) before it's considered
+    // settled. Advisory only — see `internalChecksFilter` above.
+    {
+      matchUpdateTypes: ["major"],
+      minimumReleaseAge: "30 days",
+    },
+    {
+      matchUpdateTypes: ["minor"],
+      minimumReleaseAge: "20 days",
+    },
+    {
+      matchUpdateTypes: ["patch", "digest", "pin", "rollback"],
+      minimumReleaseAge: "10 days",
+    },
     // material3 is deliberately pinned to the 1.5 *alpha* line for the
     // Expressive APIs (see gradle/libs.versions.toml). Follow the alpha train
     // but keep it in its own PR, reviewed in isolation; revisit the pin when