ADFA-4128: date the headline speedup and drop the slower-phone claim

"about 5x" carried no date and no pass id, so a reader could not tell
which run it came from -- and it matched a pass that has since been
superseded. State the range the current run measured and cite the run.

"The gain is bigger on slower phones" is no longer true: that phone's
numbers reversed in the current pass, and they are under investigation.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HZEZKHy8dkDGJM3nUut6hJ

Author: fryanpan

docs/adr/0016-quick-build-compiles-outside-gradle.md

@@ -31,7 +31,7 @@ The first three cannot be sped up or skipped.
 
 **Positive**
 
-- The edit loop is about 5x faster, and the gain is bigger on slower devices.
+- The edit loop is 4-6x faster, measured in the 2026-09-05 to 09-07 benchmarking run against the initial experimental Quick Build release.
 - The compiler stays warm between edits - the biggest single latency lever, and something Gradle cannot do.
 - A compiler crash kills the daemon, not the IDE, and the daemon can be shut down to give Gradle its memory back.
 

quickbuild/README.md

@@ -2,7 +2,7 @@
 
 Quick Build makes the on-device edit loop much faster. Tap the lightning-bolt button once and **CoGo** (Code On The Go, this IDE) installs a generated **proxy app** - a live-reloading build of the user's project. From then on every compatible save reaches the running app in seconds, with no Gradle build and no reinstall. The whole loop runs on device - edit, watch, compile, dex, deploy, reload.
 
-Measured against a standard incremental Gradle build of the same edit on real devices, Quick Build gives **about a 5x median speedup** on a warm edit. The gain is bigger on slower phones.
+Measured against a standard incremental Gradle build of the same edit on real devices, Quick Build gives a **4-6x speedup** on a warm edit. Measured in the 2026-09-05 to 09-07 benchmarking run, against the initial experimental Quick Build release.
 
 Three things that number does not say: