Closes the literal/const drift gap that F.5 introduced. Per
feedback_isv_for_adaptive_bounds + feedback_single_source_of_truth_no_duplicates:
adaptive bounds belong in ISV (or in a single canonical const that
ISV references), never duplicated as literals across modules.
Single canonical source: `crate::rl::common::FRD_HORIZON_TICKS` +
`FRD_BUCKET_RANGE_SIGMA` (already declared in F.5).
Producer-side fixes:
* Trainer ISV bootstrap (integrated.rs): the seed values for slots
500-503 now dereference the canonical consts instead of hardcoded
60.0/300.0/1800.0/3.0 literals. Future tuning of the consts
automatically propagates to both ISV seeds and loader-side
labels — no manual sync required, no drift possible.
* compute_frd_labels (loader.rs): takes `horizon_ticks` and
`range_sigma` as parameters instead of reading consts directly.
Caller (the file-load closure) sources them from the new
MultiHorizonLoaderConfig fields.
Consumer-side fixes — 8 MultiHorizonLoaderConfig literal sites now
provide the two new fields, all defaulting to the canonical consts:
* crates/ml-alpha/src/data/loader.rs (2 internal test-fixture sites)
* crates/ml-alpha/tests/multi_horizon_loader.rs (2 sites)
* crates/ml-alpha/examples/alpha_train.rs (2 sites)
* crates/ml-alpha/examples/alpha_rl_train.rs (2 sites)
* crates/ml-backtesting/src/harness.rs (1 site)
* crates/ml-backtesting/tests/{trainer_parity,ring3_replay}.rs (2 sites)
The "optimal by default" property is preserved: every caller that
doesn't explicitly override gets the spec-recommended 60/300/1800
ticks + ±3σ. Callers that need to retune set the config fields, and
the trainer's ISV slots provide a runtime knob for the same numerics.
Verification (RTX 3050 Ti):
* cargo check -p ml-alpha -p ml-backtesting --examples --tests → clean
* cargo test --lib (6/6 unit tests for FRD label gen + loss_balance) → pass
* frd_head 10/10 + integrated_trainer_smoke 1/1 + trade_mgmt 5/5 → pass
* audit-rust-consts → 0 flags
The two new MultiHorizonLoaderConfig fields are required (no Default
impl) — callers MUST opt in to the FRD label-generation contract by
naming the fields. This is the same discipline applied across other
config consumers; making them Option<...> would silently default to
"no FRD labels" and break F.4's expected supervised signal.