radio: skip Clay profile build (failed) — accept 2015-s7e19 Q&A as noisy

First attempt at Clay's voice profile from 2015-s7e19 produced
Clay-vs-Mike cosine similarity of 0.994 — essentially a Mike clone.
Root cause: 10s WavLM x-vector chunks averaged Mike's frequent
interjections together with Clay's dialogue, and Mike's well-trained
profile dominated the resulting embedding signal.

Mike's call: skip Clay, accept the 2015-s7e19 Q&A as noisy. Clay rarely
appears in other episodes, so the cost of not having his profile is
bounded to this one episode plus any rare future appearances.

Cleanup:
- voice-profiles/clay/ removed
- voice-profiles/profiles.json: Clay entry removed
- Memory updated to record the decision and the failure mode

Kept build_clay_profile.py in-repo as documentation of the attempt and
the Mike-similarity-filter pattern. Useful starting point if a future
attempt provides cleaner pure-Clay timestamps.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/memory/radio_show_no_cohost_named_tom.md

@@ -38,7 +38,7 @@ In **2015-s7e19** (Jan 2015 New Year episode):
 ### Recurring guests / fill-ins
 | Person | Affiliation | Confirmed in audio | Profile built |
 |---|---|---|---|
-| **Clay** | "Nerd Junkies" — fills in for Tara when she's out (Mike: rarely appears in other episodes) | 2015-s7e19 (throughout — Tara was out, Clay covered) | pending |
+| **Clay** | "Nerd Junkies" — fills in for Tara when she's out (Mike: rarely appears in other episodes) | 2015-s7e19 (throughout — Tara was out, Clay covered) | **skipped** — first attempt failed (Clay vs Mike sim = 0.994); Mike chose to accept 2015-s7e19's Q&A as noisy rather than build cleanly. Mike's rationale: Clay is rare in other episodes, so the cost of not having his profile is bounded |
 
 Tara's role is explicit per transcript at 2015-s7e19 @ 00:51: "in Tara's place, we have Clay. Clay from the Nerd Junkies." — Tara is the regular co-host for that era; Clay is a fill-in.