docs: retire "change bundle" wording in living-truth prose

Update architecture documentation and conventions to reflect folder-to-file migration.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: lesnik512

CLAUDE.md

@@ -70,5 +70,5 @@ executor's plan in git-ignored scratch (`.superpowers/`), and run
 `architecture/` (repo root) is the living truth about what this repo does now —
 one file per capability plus `glossary.md`, no frontmatter, authored lazily.
 **When a change alters a capability's behavior, update the matching
-`architecture/<capability>.md` in the same PR.** The change bundle in
+`architecture/<capability>.md` in the same PR.** The change file in
 `planning/changes/` stays as the *why*.

architecture/README.md

@@ -6,7 +6,7 @@ language). These files carry **no frontmatter** and are dated by git.
 
 **Promotion rule:** when a change alters a capability's behavior, hand-edit the
 matching `architecture/<capability>.md` in the **same PR** as the code — the edit
-rides in the same diff and is reviewed with it. The change bundle in
+rides in the same diff and is reviewed with it. The change file in
 `planning/changes/` stays as the *why*; this directory stays *true*.
 
 Capability files and `glossary.md` are authored **lazily** — each appears when the