[codex] prepare flavor 0.3.0

[PerishCode]

Summary

• removes the TypeScript/Vue/Svelte failure-surface and if-throw detection path from flavor
• removes raw/structured failure facts, aggregate scan state, rule descriptors, and tests
• bumps flavor-cli to 0.3.0

Validation

• cargo fmt --all --check
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo test --locked --workspace
• cargo run --locked -p flavor-cli -- check --root . --config flavor.json
• python3 scripts/dev/antlr.py check
• residual rg search for failure-surface/raw_failure/structured_failure/if-throw terms