feat(components): orchestrate signed extension registries

[ZhiXiao-Lin]

Summary

• add deterministic review/apply component plans, exact release resolution, preflight checks, and cross-process component locks
• replace reachability-only registry administration with pinned-root TUF configuration and full metadata verification
• resolve signed external Use packages through trusted registries and bind registry identity, metadata versions, target identity, and archive digest into the umbrella plan
• preserve signed registry provenance during update checks and upgrades, querying only the recorded registry and channel
• delegate the exact reviewed package and inner registry-plan digest to A3S Use
• select the existing ring provider explicitly for Codex TLS when the TUF dependency also brings AWS-LC into the process

Safety properties

• registry refresh and dry-run never download package targets
• apply recomputes and verifies the outer plan before delegation
• ambiguous package sources, registry identity drift, expired metadata, root mismatch, rollback, and semantic-version downgrade fail closed
• signed installs reject --allow-unsigned; local unsigned packages still require both explicit --from and --allow-unsigned
• an unchanged signed target converges without download or activation

Validation

• cargo fmt --all -- --check
• standalone CI graph: cargo clippy --all-targets -- -D warnings
• cargo check --workspace --all-targets --all-features --locked
• cargo test --test remote_registry_components (3 passed, 1 real-Use E2E ignored)
• cargo test --test administration_contract
• cargo test --test component_commands
• cargo test --test component_lifecycle
• registry unit tests and Codex real-wire TLS regression tests

Stack

• stacked on CLI feat(tui): prepare Use before the first model turn #35
• requires feat(extension): add signed remote registries Use#3 at 1b2a60d9c8930dcc9935b6841ed4a7778111f884

Batch journals, crash recovery, DeepResearch work, and unrelated checkpoint changes are intentionally excluded.

[ZhiXiao-Lin]

Follow-up validation for f51fa9b completed in an isolated published-dependency mirror.

Additional hardening in this commit rejects symbolic-link and hard-link operation locks without truncating their targets, verifies lock identity/ownership on Unix, adds four regression tests, and splits the oversized command/plan modules.

Validation:

• cargo fmt --all -- --check
• cargo test components::lock::tests — 4 passed
• cargo clippy --all-targets -- -D warnings
• cargo check --workspace --all-targets --all-features --locked
• component unit tests — 29 passed
• registry/use unit filter — 19 passed, 1 network test ignored
• remote registry integration — 3 passed, 1 real-a3s-use E2E ignored
• administration contract — 5 passed
• component commands — 17 passed
• component lifecycle — 6 passed
• git diff --check

A local x86_64-pc-windows-msvc cross-check was also attempted. It stopped while compiling aws-lc-sys because this macOS host has no Windows SDK (windows.h missing); no Rust diagnostic was emitted before that environment limitation.

[ZhiXiao-Lin]

Integrated through #40 at merge commit c252583e413f70a4cb265012d776f9d050b94de5. The consolidated v0.9.7 branch contains this PR's latest head f51fa9b78c970de76b43dc423981a182444b3775 and passed Linux, macOS, and Windows CI.