feat(rsky-daemon): notify on space registration

[rishibalakrishnan]

Summary

Stacked on #233 (feat/space-host-main-port). Adds direct, authenticated daemon intake so a newly registered space is notified immediately instead of waiting for periodic discovery.

Changes

• Add method-bound JWT intake with replay protection and deterministic idempotency.
• Add generation fencing, durable SQLite intake state, supervision, respawn, and tombstones.
• Preserve periodic discovery as reconciliation and rollback protection.
• Add daemon intake and persistence tests.

Verification

• cargo fmt -p rsky-daemon -- --check
• cargo clippy -p rsky-daemon --all-targets --no-deps -- -D warnings
• cargo test -p rsky-daemon
• cargo build --release -p rsky-daemon
• git diff --check

The branch is intentionally dependent on #233.