docs: align quickstart with @auto optimization

[FrozenArcher404]

Summary

Stacks on #65 and turns its proposed quickstart into the shipped @auto workflow-optimization contract.

• keeps the useful first-call → measure → review → publish → same-model-id payoff
• replaces bitrouter/auto with the only public virtual model, @auto
• replaces the unpublished agent package and placeholder eval command with guided bitrouter init / bitrouter optimize setup discovery
• documents that both strong and economy workflow requests always pass through a private BitRouter daemon; provider choice only changes outbound transport/auth
• documents the white-box quality/cost authority split, versioned intent/lock/contract, explicit adaptive consent, rollback, and current fail-closed scope
• updates stale policy.writeback, launch, and headless init examples
• regenerates the CLI reference from the current OSS binary and adds missing optimize, eval, and trajectory sections
• makes CLI generation fail when a future top-level command is not assigned to a docs section

Why this differs from #65

#65 correctly identified the best information architecture, but explicitly described unshipped surfaces. The OSS implementation now has a more general contract:

• the stable public model is @auto
• no task labels or expected answers are injected into online routing
• project-owned workflows are discovered or pinned as argv
• a generic agentic evaluator owns quality; daemon settlement owns cost/latency/route facts
• provider subscriptions, Cloud OAuth, BYOK, and local models remain behind the same daemon boundary
• publication is a separate lineage-checked action and optimization artifacts are version-controlled

This PR documents those facts rather than preserving design placeholders.

Dependencies

• base: docs: rewrite the quickstart around bitrouter/auto and the optimize loop #65
• OSS UX and routing implementation: feat: guide @auto workflow optimization bitrouter#779
• foundational optimization loop: feat(optimize): add agentic workflow loop bitrouter#777 (merged)

Validation

• pnpm lint:docs — 50 docs across 7 sections
• pnpm test — 83 tests
• BITROUTER_BIN=<current OSS binary> pnpm build — 279 pages
• git diff --check
• no Superpowers-specific content added

[FrozenArcher404]

Checkpoint at 3b14286, generated from the installed PATH binary for OSS ba9ceb0b (SHA-256 d5f9a3fc8b4a71d5dcd67aa5f6f63f4f0143abee862404fe9a43489a670d4e46). The docs now match model-neutral onboarding: reuse existing @auto tiers, otherwise prompt on a TTY or require explicit strong/economy flags headlessly; no model or synthetic-price default is documented or emitted by the CLI. Validation: 136 CLI commands captured, 50-doc authoring lint, 83/83 tests, 279-page production build, diff check, and no Superpowers path touched.

[FrozenArcher404]

Final docs validation is complete against an installed bitrouter 1.0.0-alpha.27 binary from a clean default environment.

The documented UX matches the real CLI and E2E path: @auto is the only public model name; both strong and economy workflow calls traverse BitRouter daemon routing; Codex subscription and BitRouter Cloud OAuth coexist as tier-specific outbound authorities; direct ACP is evaluator-only; setup/run/review/publish/rollback commands and the explicit adaptive-publication consent all executed successfully. The measured candidate preserved a passing workflow result while reducing normalized showback by 47.6644%, and live-daemon rollback restored the original route and lineage.

The docs-site build is green, the branch is CLEAN/MERGEABLE, and this PR introduces no Superpowers-specific content.