docs: title the homepage with the mission, and fix the App install step

docs/getting-started.md

@@ -5,10 +5,11 @@ commit message on your machine, and wired into the two places it belongs.
 
 It takes about five minutes and needs nothing but a Git repository.
 
-!!! tip "On GitHub and want nothing to install?"
+!!! tip "On GitHub? The App needs no local setup"
 
-    [Install the GitHub App](https://github.com/apps/commit-check): every push
-    and pull request gets a **Commit Check** result, with no workflow file. The
+    [Install the GitHub App](https://github.com/apps/commit-check) on the
+    repositories you want checked: every push to a branch and every pull request
+    in them gets a **Commit Check** result, with no workflow file. The
     [App guide](guides/github-app.md) covers what it checks. This page sets up
     the CLI and the hook, which work with any Git host.
 

docs/guides/github-app.md

@@ -15,10 +15,11 @@ report the same rule IDs, so running both is fine.
 
 ## Install
 
-On the Marketplace page, pick the account to install on. For an organization,
-choose **All repositories** and every repository, including ones created later,
-is covered; with **Only select repositories**, only those are checked and new
-ones have to be added by hand. A personal account works the same way.
+On the [App's page](https://github.com/apps/commit-check), click **Install** and
+pick the account to install on. For an organization, choose **All
+repositories** and every repository, including ones created later, is covered;
+with **Only select repositories**, only those are checked and new ones have to
+be added by hand. A personal account works the same way.
 
 There is nothing to add to a repository. A repository that already has a
 `cchk.toml` or `commit-check.toml` is checked against it from the next push. One
@@ -33,7 +34,8 @@ On every push to a branch and on every pull request, each commit gets a check
 run named **Commit Check** (a push of more than 50 commits has its newest 50
 checked, and the older ones get one neutral "not checked" result) on the Checks tab, in the commit's status and in the
 merge box. (Tag pushes and branch deletions carry nothing to check; commits by
-bots are skipped, and squash mode checks a pull request as one message — both
+bots are skipped, except for AI coding agents that commit as an app, and squash
+mode checks a pull request as one message — both
 [below](#bots-re-runs-and-commits-checked-twice).) The result reads the same
 way everywhere:
 

docs/index.md

@@ -4,7 +4,7 @@ hide:
   - toc
 template: landing.html
 title: Commit Check
-seo_title: Commit Check — Commit message & branch name linter for Git
+seo_title: Commit Check — Commit policy as code for teams and AI agents
 description: Commit policy as code for teams and AI agents. Messages, branches, authors and AI attribution, checked from your commit hook to every pull request.
 ---