Anchor lane-selector legality to the omp registry

[hieusats]

Closes #10

What changed

provider-dispatch.md stops presenting the four-family Model matrix as the legality domain of a lane selector. The section is now ## Provider panel: the table stays as the first-run default group plus the external CLI lanes, and a native lane selector is legal when omp models lists its provider and model, with the registry's listed thinking levels as its selectable efforts. The parent route table generalizes from provider prefixes (claude:*, codex:*, grok:*) to lane type, because an omp registry can serve any provider natively. setup-pstack accepts registry-native rows and gains a registry-native first-run path (one selector per uncovered lane) for installs whose registry serves none of the panel families, instead of dead-ending on four failed frontier probes. skill-collision-repro.sh reads the unchanged quad from the renamed section. Version bumps to 2.1.3.

Verification

• Bun tests, strict typecheck, static invariants, and plugin validation pass.
• The exact candidate is installed in every affected harness.
• The changed behavior passes from each real user surface.
• The installed version, action, and observed result appear below.

Live evidence:

• Red-first: 3a844f3c26 pins the new contract; run before the fix it fails with error: missing ## Provider panel (model-matrix.test.ts).
• Green after the fix: plugin suite 169 pass, repo suite 18 pass, skill-collision-repro.sh all ok including the quad check against the renamed section, tsc --strict clean, version chain 2.1.3 across UPSTREAM.md and both manifests.
• Installed candidate: omp plugin upgrade pstack@omp-pstack from the local marketplace source. bun run tests/verify-installed-version.ts prints pstack repo 2.1.3 | served 2.1.3 | cache 2.1.3, and the installed provider-dispatch.md contains ## Provider panel (1 match).
• Real omp session, surface omp -p: a fresh session told to read skill://poteto-mode/references/provider-dispatch.md replied verbatim with the new legality sentence, "A native lane selector is legal when omp models lists its provider and model; its selectable efforts are the thinking levels the registry lists for that model, and the panel's Selectable efforts cells govern only the panel families."
• Real omp session, lane dispatch on this registry-native host (omp models serves only zai): a fresh session dispatched one pstack-scout task agent over the live zai/* sheet and the scout replied READY.
• User state restored: marketplace back on hieusats/omp-pstack; installed 2.1.3 retained.