feat(docs): reposition CoreRoom around issue-to-PR evidence

[spytensor]

Problem

CoreRoom's README and first public explanation describe many correct mechanisms — roles, TUI, journals, permissions, gates — but an external user does not immediately see the differentiated product value: CoreRoom is the AI engineering control plane that turns agent work into issue-scoped, PR-backed, evidence-carrying delivery.

This matters because Claude Code, Codex, Gemini CLI, and GitHub Copilot already cover "agent writes code" and increasingly cover multi-agent/background work. CoreRoom must make the evidence/control-plane delta obvious in the first screen.

Proposed solution

Reposition the README top section and first-run narrative around the killer loop:

issue / user-scoped intent -> @host intake -> scoped work -> agent execution -> PR evidence -> reviewer decision

Concretely:

• Lead with the issue-to-PR evidence loop, not the roster/TUI feature list.
• Add a short "Why not just Claude Code / Codex / Copilot?" contrast focused on governance, evidence, and cross-engine control.
• Add a 90-second demo script showing a realistic issue, acceptance criteria, branch/PR evidence, risks, rollback, and tracker handling.
• Keep install/update instructions accurate and avoid unverified market claims.

Alternatives considered

• Keep the README as a feature inventory. Rejected: it makes CoreRoom look like a multi-agent terminal cockpit, which is not defensible against vendor CLIs.
• Build more UI first. Rejected: users must understand why the product exists before more UI polish matters.

Scope target

v0.x or later (deferred is fine)

Acceptance criteria

• README top section explains CoreRoom as an AI engineering control plane / evidence layer before listing role/TUI mechanics.
• README includes a concise killer-loop walkthrough from issue or user-scoped intent to PR evidence.
• README explicitly states what CoreRoom does not replace: agent runtimes, GitHub PRs, CI, reviewer judgment.
• Any comparisons to Claude Code, Codex, Gemini CLI, or Copilot are phrased as positioning, not unverifiable superiority claims.
• Install/update instructions and current version facts remain aligned with Cargo.toml, npm/package.json, and AGENTS.md.

Validation

• python3 scripts/check-project-truth.py
• git diff --check
• Manual README pass: a new user can explain the killer loop in one sentence after reading the first screen.

Out of scope

• No runtime behavior changes.
• No new screenshots unless existing README visuals become misleading.
• No claims of external adoption unless independently evidenced.

[spytensor]

Tracking umbrella: #408. This issue is part of the direct user-scoped CoreRoom control-plane polish batch opened on 2026-05-28.