docs(installer): drop phase references that are now this build's behaviour

Five comments described the patch tier as work a later phase would do. It is
this phase, so they read as stale the moment the code landed.

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

src/record.rs

@@ -44,7 +44,7 @@ pub struct InstallRecord {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub link: Option<serde_json::Value>,
     /// The patch tier: one entry per feature actually in place, with the rung that applied each of
-    /// its patches (Phase 3).
+    /// its patches.
     ///
     /// Raw JSON for the same reason as [`InstallRecord::link`] — a record written by a newer
     /// installer survives a re-run here intact. Read it with [`InstallRecord::patch_records`].