refactor(persona): the copy outside the pane speaks the vocabulary too

[stormer78]

Third of three PRs bringing the persona vocabulary into sync across the stack:

• verifiable-trust-infrastructure#1291 — pnm persona …
• vta-browser-plugin#183 — the console's persona pane (which was also stale)
• this one — the OpenVTC copy outside the identity pane

#280 brought the pane over and left the rest for "when next touched".

What changed

The join flow's identity choice — "Who should this community know you as?",
"Choose the persona this community will know you as", "Already known to:",
"Be someone new to this community" — the invitation list, and the communities
panel's empty state.

The reuse warning is the one that matters. It is the last thing a person
reads before linking themselves across two communities, and it now carries the
table's sentence verbatim:

Being known here as "Work me" makes you the same person to anyone who sees
both this community and the others using it.

The point of a fixed phrase is that meeting it twice teaches it. A paraphrase in
one surface spends the recognition and gives nothing back.

What I deliberately left alone

profile in setup, backup and --profile. That is the config profile — a
local installation profile that predates the persona family, has its own meaning
to operators, and appears in a flag they type. It is exactly the collision the
vocabulary doc cites when it declines to use "profile" for a face; renaming it
here would manufacture the confusion the table exists to prevent.

Pre-merge checklist (vti-stack-development-guide §9)

- [x] No new clients/timeouts (R1.2) — copy only
- [x] No lock held across a network await (R1.3)
- [x] No local state before its remote effect (R2.1)
- [x] Retries bounded (R1.4) — none added
- [x] Loops survive transient errors (R1.5) — n/a
- [x] Acks after durable handoff (R1.6) — n/a
- [x] Wire types (R3.*) — none changed
- [x] Config absence = most restrictive (R5.*) — unchanged
- [x] Logs/status claim only what was verified (R6.*) — the linkage warning
      keeps its exact claim, in the shared wording
- [x] "Process dies on the next line" (R2.1) — n/a
- [x] Deviations — none

cargo test --workspace green (426 in the binary); clippy -D warnings clean.