feat: plan native host hooks and process environment targets

[roodboi]

Native config can now declare host lifecycle hooks and processes and inspect their managed environment bindings offline. Ordered up/down hooks and named processes preserve explicit argv or shell, checkout-relative cwd, startup/exit intent and process singleton settings. Each entry selects the generic host environment or an explicit declared service/job; matching names do not grant implicit scope.

Rust owns validation and binding decisions. The existing env owner preserves worktree/overlay precedence and returns only requested key/scope/secret metadata. Required references and remapping collisions refuse with original declaration pointers. Validation never reads managed env documents; planning never decrypts values or executes hooks/processes. A shared pre-allocation output budget prevents many invocations from amplifying one baseline into an oversized report. Hostless compiler compatibility and serialized identities are preserved.

Validation: fresh full CLI gates passed (2,405 tests, 68 skips, zero failures; DB task reused valid cache), 57 Rust tests plus format/Clippy, 160 independent schema/Rust cases, 72 owner tests, 127 transport tests, actual relocated CLI/sidecar acceptance without host Bun/Rust, staged privacy, changed-file lint, workflow checks and independent review. A complete signed private candidate passed isolated installation, installed host planning/offline validation/incomplete-reference refusal, repeat-install home identity preservation and deselect/refuse/reselect. No tag, release, existing channel or app changed. The compiler CI lane runs the new host acceptance on Linux and macOS; all ten hosted CI jobs plus Graphite passed on exact head 3b63734 (CI run).

Release intent: feat adds experimental native configuration planning. Native execution/Compose lowering, post-hook generation admission, secret delivery and locked adoption remain later integration work; this does not make native-authored projects runnable.