refactor(kanban-orchestrator): drop hardcoded specialist roster, add Step-0 profile discovery

The skill enumerated 8 specialist profile names (researcher, analyst,
writer, reviewer, backend-eng, frontend-eng, ops, pm) as "the standard
roster" and told orchestrators to "assume these exist." Almost no real
Hermes setup matches that fleet — single-profile setups, Docker-worker
setups, and curated-team setups all violate it — so following the skill
literally produced cards assigned to non-existent profiles, which the
dispatcher silently failed to spawn (no autocorrect, no fallback, just
sits in `ready` forever).

Changes:

- Drop the standard-specialist-roster table.
- Add a "Profiles are user-configured — not a fixed roster" section at
  the top with a Step 0 that prescribes `hermes profile list` (or asking
  the user) before fanning out. Cache the result in working memory.
- Rewrite the worked task-graph example with placeholder names
  (<profile-A>, <profile-B>, <profile-C>) so the structure is still
  teachable but doesn't invite copy-paste of role names that may not
  exist.
- Reframe the "If no specialist fits" anti-temptation rule: don't
  invent profile names; ask the user.
- Add a "Inventing profile names that doesn't exist" entry to Pitfalls.
- Bump skill version 2.0.0 → 3.0.0 (semantic break: previous behavior
  promised a roster the skill no longer enumerates).
- Update website/docs/user-guide/features/kanban.md to drop the
  matching "(researcher, writer, analyst, backend-eng, reviewer, ops)"
  line and explain the discovery prompt instead.
- Re-run website/scripts/generate-skill-docs.py to refresh the
  auto-generated skill page + catalog.

Closes #21131 in spirit — addresses the same hardcoded-names footgun
@yehuosi flagged, with a different shape than their PR (delete the
roster rather than replace each name with placeholder, since the
roster table was the load-bearing footgun and the worked example is
salvageable with placeholder profile names).

Co-authored-by: yehuosi <yehuosi@users.noreply.github.com>

scripts/release.py

@@ -716,6 +716,8 @@ AUTHOR_MAP = {
     "5463986+baocin@users.noreply.github.com": "baocin",
     "107296821+princepal9120@users.noreply.github.com": "princepal9120",
     "gufo0125@gmail.com": "guglielmofonda",
+    "102474490+yehuosi@users.noreply.github.com": "yehuosi",
+    "yehuosi@users.noreply.github.com": "yehuosi",
     "23434080+sicnuyudidi@users.noreply.github.com": "sicnuyudidi",
     "haimu0x0@proton.me": "haimu0x",
     "abdelmajidnidnasser1@gmail.com": "NIDNASSER-Abdelmajid",