Lighten the comment load

Drops porting-history narratives (dodrenett), superseded-behavior
explanations, and restatements of what the next line does. Constraint
notes (fail-closed policies, CAS semantics, cascade behavior, id
uniqueness) stay, just shorter. No code changes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/upload.rs

@@ -24,11 +24,9 @@ pub struct Garage {
 }
 
 impl Garage {
-    /// Builds a client from `GARAGE_S3_ENDPOINT`/`GARAGE_ACCESS_KEY`/
-    /// `GARAGE_SECRET_KEY`/`GARAGE_UPLOADS_BUCKET` - same secret names
-    /// dodrenett's own Woodpecker pipeline already uses. `None` (not an
-    /// error) when unset, since uploads are optional: everything else
-    /// works without Garage configured.
+    /// Builds a client from the `GARAGE_*` env vars. `None` (not an
+    /// error) when unset - uploads are optional, everything else works
+    /// without Garage configured.
     pub fn from_env() -> Option<Self> {
         let endpoint = std::env::var("GARAGE_S3_ENDPOINT")
             .unwrap_or_else(|_| "http://garage:3900".to_string());