v0.12.3 — direct native claim for strict writers

Fixed

• Expose native gvozd_claim directly with codemode:false while retaining exact permission and all lease guards.
• Cartographer and Docs can claim leases without opening execute or adding MCP grants.
• Update direct-call prompts and add host catalog, transport and native execution regression coverage.

Verified

651 tests, lint/typecheck/build, sync/package/release-tag gates, 4 e2e tests and Linux/macOS CI pass.
Actual OpenCode 2.0.24 with the rebuilt local plugin passes isolated native smoke: parent reservations, child claim/edit, strict writers without execute, readonly no-claim, and four rejections per writer (preclaim, wrong assignee, wrong parent, out-of-lease). Denied writes remain unchanged; final idle wait and cleanup pass.
Deep feature review and release metadata review: APPROVE.

No dependency/compatibility changes or global installation changes. Live smoke currently requires local macOS paths; production installation is not covered by the isolated result.

PR: #16