docs: shorten cache interceptor comments

Collapse the multi-sentence comments introduced by this PR to the terse,
single-line style used elsewhere in lib/interceptor, keeping the RFC 9111
references. Addresses proactive review feedback on comment terseness.
No logic change.

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

Author: EC2 Default User

lib/handler/cache-handler.js

@@ -26,10 +26,8 @@ const NOT_UNDERSTOOD_STATUS_CODES = [
 
 const MAX_RESPONSE_AGE = 2147483647000
 
-// How long revalidation-only entries (zero freshness lifetime but a validator
-//  present, e.g. `cache-control: no-cache` or `max-age=0` with an etag) are
-//  retained so there is something to revalidate against. Every successful
-//  revalidation re-stores the entry, sliding this window.
+// Retention for revalidation-only entries (zero freshness lifetime but a
+//  validator present); each successful revalidation re-stores the entry.
 const REVALIDATION_ONLY_RETENTION = 86400000 // 24 hours
 
 /**
@@ -169,10 +167,8 @@ class CacheHandler {
 
     const baseTime = resDate ? resDate.getTime() : now
     const absoluteStaleAt = staleAt + baseTime
-    // Responses with a zero freshness lifetime but a validator (e.g.
-    //  `cache-control: no-cache` or `max-age=0` with an etag) are stale from
-    //  the start, but they're still storable - each reuse is preceded by a
-    //  revalidation request.
+    // Zero freshness lifetime but a validator: stale from the start, yet still
+    //  storable since each reuse is preceded by a revalidation request.
     //  https://www.rfc-editor.org/rfc/rfc9111.html#section-5.2.2.4
     const revalidationOnly = staleAt === 0 && hasValidator
     if (now >= absoluteStaleAt && !revalidationOnly) {
@@ -454,8 +450,7 @@ function determineStaleAt (cacheType, now, age, resHeaders, responseDate, cacheC
         return sMaxAge * 1000
       }
 
-      // An immediately stale response can still be stored if we can
-      //  revalidate it before reuse
+      // Immediately stale, but storable if we can revalidate it before reuse.
       return sMaxAge === 0 && hasValidator ? 0 : undefined
     }
   }
@@ -466,8 +461,7 @@ function determineStaleAt (cacheType, now, age, resHeaders, responseDate, cacheC
       return maxAge * 1000
     }
 
-    // An immediately stale response can still be stored if we can revalidate
-    //  it before reuse
+    // Immediately stale, but storable if we can revalidate it before reuse.
     return maxAge === 0 && hasValidator ? 0 : undefined
   }
 
@@ -513,8 +507,7 @@ function determineStaleAt (cacheType, now, age, resHeaders, responseDate, cacheC
   }
 
   if (cacheControlDirectives['no-cache'] === true && hasValidator) {
-    // The response has no freshness source, but, since it has a validator,
-    //  it can still be stored and revalidated before each reuse
+    // No freshness source, but a validator lets us revalidate before reuse.
     //  https://www.rfc-editor.org/rfc/rfc9111.html#section-5.2.2.4
     return 0
   }
@@ -556,11 +549,8 @@ function determineDeleteAt (baseTime, cachedAt, cacheControlDirectives, staleAt)
   if (staleWhileRevalidate === -Infinity && staleIfError === -Infinity && immutable === -Infinity) {
     const freshnessLifetime = staleAt - baseTime
     if (freshnessLifetime <= 0) {
-      // Revalidation-only entry (zero freshness lifetime, stored solely so
-      //  reuses can be revalidated with a conditional request): there's no
-      //  freshness lifetime to base the buffer on, so retain it for a bounded
-      //  window instead. Every successful revalidation re-stores the entry,
-      //  sliding the window.
+      // Revalidation-only entry: no freshness lifetime to size the buffer on,
+      //  so retain it for a bounded window instead.
       return cachedAt + REVALIDATION_ONLY_RETENTION
     }
     const datePrecisionPadding = Math.min(Math.max(cachedAt - baseTime, 0), 1000)