Present the skill decomposition position outside the architecture documentation

[dieterbaier]

Goal

Present the position recorded in ADR-008-skill-decomposition-boundary outside
the architecture documentation, where the people who ask the question actually
are.

Why

Role-based agent architectures — a planner, a coder, a reviewer, each a separate
agent — are common, and teams building one reach the same question this toolkit
already answers: on which axis is the process knowledge cut, and where does the
role-to-skill binding live. ADR-008 answers it, but an ADR inside this
repository's own arc42 is not where that audience looks.

The answer is also not adversarial, which is the part worth carrying outward. A
platform that decomposes its agents by role does not thereby cut its skills
by role. Such a platform sits inside ADR-008's accepted option: the toolkit is
the layer underneath it, not a competitor to it.

What to present

The ADR already contains the material; this is a presentation task, not a new
decision. The pieces that carry outward:

• The three questions usually asked as one — cut, allocation, agent
  decomposition — and which of them the toolkit decides.
• The honest comparison, including where a persona cut genuinely wins:
  organisational mappability, and independence of verification.
• The orchestration illustration from the ADR's Decision, which allocates an
  entry skill per role rather than a list of skills, so the allocation is
  closed under delegation by construction. ADR-008 deliberately does not
  maintain this as an example; if it is shown outside the ADR, this issue is
  where it gets a home.
• R-007-gate-results-lack-independence as the cost the position accepts, so
  the presentation does not read as a sales pitch.

Venue is the open decision

Candidates, to be chosen when this is picked up rather than now:

• README.md, next to the capability presentation from Slice #77.1: Present the toolkit through features in the README #80;
• a talk under talks/, alongside the existing meetup material;
• a dedicated document outside arc42.

Pick one. The ADR stays the single source; whatever is written points back to it
rather than restating the argument, so the two cannot drift.

Acceptance criteria

• The position is readable by someone who has never opened this repository's
  arc42.
• The three axes and the toolkit's answer are stated without requiring the
  full ADR.
• The rejected options keep the strengths ADR-008 credits them with.
• The accepted cost (R-007) is named, not omitted.
• The material references ADR-008 as the source instead of restating the
  decision.
• No new decision is introduced; anything that turns out to be one goes back
  into an ADR first.

Origin

Proposed by the owner while accepting ADR-008 in #88: the illustration does not
need to be maintained inside the repository, but it would be worth reusing if
the decision is presented outside the architecture documentation.