refactor: DELETE trapfall-dashboard ghost crate (3 LOC stub)

[ajianaz]

What

Delete trapfall-dashboard crate (3 LOC stub containing only // TODO: Phase 0 — scaffold only).

Why

BMAD COO finding: Dashboard serving is implemented in trapfalld/src/spa.rs (62 LOC) using rust-embed to serve the SvelteKit web/build/ output. The standalone trapfall-dashboard crate is a stub with zero implementation. Same organizational fiction as trapfall-alert.

Changes

1. Remove trapfall-dashboard/ directory entirely
2. Remove "crates/trapfall-dashboard" from root Cargo.toml workspace members
3. Remove trapfall-dashboard dependency from trapfalld/Cargo.toml if present
4. Verify SPA serving still works via trapfalld/src/spa.rs
5. Verify cargo build --workspace passes

Testing

• cargo build --workspace — must pass
• cargo test --workspace — all 231 tests must still pass
• Verify dashboard UI loads when running trapfalld

[ajianaz]

Completed in PR #305 — trapfall-dashboard ghost crate deleted.