strip unused QuotingMetricsTracker surface, dead deps, and dead feature flag

[grumbach]

Summary

• Strip orphaned fields and helpers from QuotingMetricsTracker — the price formula reads exactly one input (close_records_stored), everything else was scaffolding without a consumer.
• Drop three unused direct dependencies (aes-gcm-siv, hkdf, self_encryption) and the dead dev Cargo feature flag.
• Re-word the pricing-module doc to remove the misleading "Phase 1 recalibration" framing.

Net: +28 / -413 across 6 files (Cargo.lock loses 76 lines on its own).

What's actually dead

QuotingMetricsTracker shipped with seven fields, but only close_records_stored is read by calculate_price (which is the only consumer). The others were either ghost infrastructure (entire persistence layer: with_persistence, PersistedMetrics, maybe_persist, Drop::persist) or values that get bundled into a QuotingMetrics struct nobody calls — received_payment_count, records_per_type, start_time/live_time, network_size. Production constructs the tracker via ::new(_), never ::with_persistence(_), so the on-disk format and debounce machinery never fired anywhere.

Cargo deps aes-gcm-siv, hkdf, self_encryption were declared for a legacy data-migration feature that was never built — zero use statements across src/. Cargo feature dev had zero #[cfg(feature = "dev")] gates.

What this PR doesn't touch

• The pricing formula itself is unchanged — only the unused metrics scaffolding around it goes.
• record_payment is removed (only fed the dropped counter); record_store loses its unused data_type parameter. The wire protocol still carries data_type through ChunkQuoteRequest and MerkleCandidateQuoteRequest, untouched.
• No external crate (ant-client, ant-protocol, evmlib, saorsa-core) imports the affected surface. Verified by grep across the workspace and ~/.cargo/registry/.

Verification

• 472 lib tests pass.
• cargo clippy --all-features --all-targets -- -D warnings clean.
• cargo fmt --check clean.
• cargo doc --no-deps --all-features with RUSTDOCFLAGS="--deny=warnings" clean.

Test plan

• CI green on ubuntu + windows
• Spot-check that downstream consumers (ant-client) build against this branch unchanged
• One reviewer sanity-checks the record_store signature change isn't load-bearing somewhere I missed

[Copilot]

Pull request overview

This PR removes unused quoting-metrics scaffolding and associated dead code paths, simplifies the storage->pricing signal to a single counter (close_records_stored), and trims unused Cargo dependencies/feature flags to reduce maintenance overhead.

Changes:

• Simplify QuotingMetricsTracker to only track close_records_stored, removing unused counters, per-type tracking, and persistence helpers.
• Update storage handler and quote generator to record only store events (remove payment recording and data_type parameter from record_store).
• Remove unused direct dependencies (aes-gcm-siv, hkdf, self_encryption), drop the unused dev feature, and refresh pricing module docs.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/storage/handler.rs	Stops recording payment/type metrics on chunk PUT; only increments stored-record counter.
src/payment/quote.rs	Removes record_payment and changes record_store API to match simplified metrics tracker.
src/payment/pricing.rs	Updates module-level documentation wording (no pricing logic change).
src/payment/metrics.rs	Replaces multi-metric + persistence tracker with a single atomic counter.
Cargo.toml	Removes dead direct deps and removes the unused dev feature.
Cargo.lock	Removes lock entries for eliminated direct dependencies and their no-longer-needed transitive packages.

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