Bump to v2.0.0: daily emote rotation + expanded sound library

- Emote face is now stable all day; /wake picks a fresh random face each
  morning instead of rotating every 5 minutes. Removes EMOTE_ROTATION_INTERVAL
  and last_emote_change entirely.
- Added 10 new synthesized sounds for /notify: doorbell, knock, ding, blip,
  siren, tada, ping, bubble, fanfare, and alarm (loops until tapped or TTL
  expires). stopAlarm() wired into tap handler and handleStateChange().
- openapi.yaml: new sound names added to enum.
- CLAUDE.md / README.md updated to reflect both changes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

openapi.yaml

@@ -313,6 +313,16 @@ components:
             - critical
             - success
             - notify
+            - doorbell
+            - knock
+            - ding
+            - blip
+            - siren
+            - tada
+            - ping
+            - bubble
+            - fanfare
+            - alarm
             - none
           example: "chime"