fix: expose uncertified DDSketch ratios in v1 demo

[zzylol]

Closes #446

Before

show_post_asap_ir used the default fail-closed strategy. A quantile-over-time ratio therefore produced only KeepPreAsap when no AccuracyEvidenceProvider supplied input-domain proofs, which blocked the v1 integration/demo path.

After

• Add an explicitly named demo-only strategy constructor for uncertified DDSketch quantile ratios.
• Keep the candidate root guarantee unset, so missing evidence is never represented as a certified accuracy bound.
• Keep all default and evidence-backed constructors fail-closed.
• Scope the relaxation to direct DDSketch quantile ratios; other approximate divisions still fall back to KeepPreAsap.
• Use the opt-in in show_post_asap_ir and document the distinction between a demo candidate and a certified plan.

Verification

• cargo fmt --all -- --check
• CARGO_TARGET_DIR=/mydata/ASAPPlanner-issue-446-target cargo test -p asap-devtools --bin show_post_asap_ir
• CARGO_TARGET_DIR=/mydata/ASAPPlanner-issue-446-target cargo test -p asap-aware-mapping quantile_ratio_without_input_proof_keeps_native_execution
• CARGO_TARGET_DIR=/mydata/ASAPPlanner-issue-446-target cargo clippy -p asap-aware-mapping -p asap-devtools --all-targets -- -D warnings