docs(personal): research Sophia properly, drop lineage from agent-facing text

Two corrections.

**1. Sophia was written from recall, not from the source.** Reworked her
identity and voice against the Golden Girls canon:

- **She has a Brooklyn accent, not a Sicilian one.** She left Sicily in the
  1920s and spent seventy years in New York; Estelle Getty played her
  explicitly as Brooklyn Italian-American. This is the single most common
  way to get her wrong, so it is now stated in the tone line, repeated in
  Avoid, and has its own failure mode.
- **"Picture it" is a parable, not a catchphrase.** It opens a scene that
  ends in a moral answering the question actually asked. The failure mode
  is using it as a verbal tic with no story behind it.
- Added the real biography (Grisanti, Salvadore, Clinton Avenue, Dorothy /
  Gloria / Phil, the stroke that removed her filter, Shady Pines, chef at
  the Golden Palace, the bamboo handbag) and the canon behaviours worth
  having: Sicilian curses, grudges, the mafia joke, serial embellishment
  with famous acquaintances.
- New example interaction demonstrating a "Picture it" that earns its place.

**2. Agents no longer get told who they replaced.** Provenance muddies the
voice, invites comparison to a character that no longer exists, and costs
context — an agent only needs to know who they *are*. Removed the lineage
sentences from Sophia's bible and prompt, and retroactively from Watson
(Seneca) and David (Bowie), including the LLM-facing shared.md directory
and the personal.md "Replaced agents" section. Watson's substantive framing
guidance is preserved, only the who-came-before is gone.

Provenance now lives in exactly two places: the schema Version History and
the git log.

New docs/roster-changes.md captures the practice — the fictional-character
casting rule and why it exists, when retiring is justified, that a 2:1
merge is legitimate, that node ownership transfers with no migration
because constraints are label-keyed, that historical Note tags are left
alone, and a checklist of everywhere a roster change actually reaches
(spoiler: every agent prompt embeds the team roster, across all three
teams and every runtime and deploy repo).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

prompts/personal/david.md

@@ -10,7 +10,7 @@ You are David, Robert's arts and culture companion — inspired by David Rose fr
 
 Your job is to **elevate Robert's taste**. Not to defer to comfortable defaults. Not to validate whatever's on the algorithm because Robert couldn't be bothered. When Robert reaches for something lazy, you push — corrective, not cruel, but the push is the point.
 
-You replaced Bowie on the team and inherited the arts-and-culture domain (Music, Film, Artwork, Playlist, Artist, Style) with the addition of Fashion. You work closely with Hypatia (literary adaptations, music theory for the *teaching* angle), Sophia (food in film — reluctantly), Cristiano (football documentaries and films), and Shawn (cultural events on the calendar).
+You own the arts-and-culture domain — Music, Film, Artwork, Playlist, Artist, Style, and Fashion. You work closely with Hypatia (literary adaptations, music theory for the *teaching* angle), Sophia (food in film — reluctantly), Cristiano (football documentaries and films), and Shawn (cultural events on the calendar).
 
 You do NOT cook. You don't know what "fold in the cheese" means and you never will. (For the record, that was Moira.)