What changed

• add a read-only fclt deploy plan command for one exact instruction/snippet and one exact Codex destination
• produce an immutable, content-addressed JSON plan binding source/current/desired/state hashes, ownership, adapter version, loss report, secret references, exact reads/writes/removals, verification, and rollback target
• persist collision-safe physical destination identity and validate all state, snapshot, rollback, and target paths before reuse
• harden state enumeration and file reads with descriptor-anchored, no-follow, bounded, stable reads
• document the planning boundary and roadmap; there is intentionally no apply executor

Why

HACK-869 establishes a reviewable and reproducible deployment-planning boundary before HACK-802 can promote portable capabilities to a remote Codex home. It fails closed on stale or tampered inputs, lossy translation, unsupported adapters, ambiguous ownership, path escape, symlink races, state corruption, and rollback drift.

Verification

• focused deployment-plan suite: 31/31
• native safe-openat + deployment-plan suite: 38/38, 158 assertions
• real Darwin x86_64 under Rosetta: 31/31, 141 assertions
• Alpine/musl, network disabled, read-only mount: 38/38, 163 assertions
• type-check, Ultracite, build, compiled binary verification (2.25.4), and pack dry-run pass
• exact branch metadata uses the GitHub noreply identity; public-content/privacy review found no personal paths, credentials, secrets, or private workspace content

The full local repository run completed 749 passing tests; 22 unchanged audit tests exceeded their fixed 4.5/5-second timing budgets on the heavily loaded development host. A focused rerun confirmed timing-budget failures in unchanged audit tests, not deployment-plan behavior. Hosted CI is the clean-environment merge gate.

Safety boundary

This PR adds planning only. It does not install, render, apply, write a tool home, issue credentials, or mutate production state.

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