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>

README.md

@@ -28,6 +28,8 @@ Subagents are minimal-personality utility agents called as tools by leads — se
 
 The lists below reflect what's currently in `prompts/{team}/` — the source of truth. When assistants are added, replaced, or retired, update the directory and these tables together.
 
+**Assistants are fictional characters** — real people carry baggage that arrives with the name and can change after the fact, while a character has canon to write against. Adding, replacing, or retiring one touches far more files than it looks like (every agent prompt embeds the team roster) — see [docs/roster-changes.md](docs/roster-changes.md) for the practice and the checklist.
+
 ### Personal Team
 | Assistant | Inspired By | Domain |
 |-----------|------------|--------|
@@ -82,6 +84,7 @@ koios/
 │       ├── hecate.md                 #     Home automation
 │       └── neo4j.md                  #     Graph usage discipline
 ├── docs/                             # Human reference + LLM context for graph/messaging
+│   ├── roster-changes.md             #   Adding/replacing/retiring assistants — practice + checklist
 │   ├── personal/                     #   Character definitions & team overview
 │   ├── work/                         #   Character definitions & team overview
 │   ├── engineering/                  #   Character definitions, team overview, subagents catalog