feat(objectives): add minimize-depot-travel-time objective

[hutchinsp01]

Motivation

Workforce wants a scheduling recipe that keeps each technician working in their local patch — assigning jobs to the vehicle whose depot (shift start) is closest to the job. The existing minimize-cost/minimize-distance objectives minimise total route travel (not per-job depot proximity), and CompactTour clusters a tour's jobs near each other (not near the depot). This adds a dedicated objective for that.

This is the uptick/vrp half of a two-repo change; the Workforce side adds a near-depot recipe that uses it (and bumps the vrp-cli dependency once this releases).

Changes

• New core feature vrp-core/.../features/depot_proximity.rs — a FeatureObjective scoring each job by the travel duration from its route's depot (route.actor.detail.start) to the nearest of the job's candidate locations (handles Single and Multi). Objective-only; no constraint or state. The DepotPenaltyFn type alias is the seam for a future non-linear penalty (linear/identity today).
• Two modes via an optional cap:
  • soft (cap = None) — a per-assigned-job penalty, intended as a member of a weighted-sum tier. Degenerate if used standalone (assigning nothing has zero travel).
  • capped "depot radius" (cap = Some(c)) — leaving a job unassigned costs c, while assigning it costs its depot→job travel. Minimising this assigns every job within c of a depot (nearest first) and drops the rest — proximity-gated assignment, safe as a dominant lexicographic tier (the empty solution costs N*c, never wins). Mirrors minimize_unassigned's handling of unassigned/ignored jobs.
• Pragmatic format: new Objective::MinimizeDepotTravelTime { cap: Option<Float> } → {"type":"minimize-depot-travel-time"} or {"type":"minimize-depot-travel-time","cap":1200.0}. Wired through goal_reader.rs.
• Version bumped to 1.25.3 (+ rosomaxa 0.9.3, lockstep) and CHANGELOG updated, so Workforce can depend on the published build.

Verification

• cargo test -p vrp-core depot_proximity — 11 unit tests (estimate at route vs activity context, nearest-of-multiple-places, Multi jobs, no-location → 0, capped reward/penalty, capped fitness penalises unassigned).
• cargo test -p vrp-pragmatic minimize_depot_travel_time — round-trip parse (with/without cap) + goal-build.
• cargo fmt / clippy clean on the changed files; full workspace cargo check passes.

🤖 Generated with Claude Code

[kraklo]

tbh I don't think I know enough of the vrp internals to check it off with full confidence, but nothing is jumping out at me and the unit tests seem to give us good confidence

[adamdickinson]

Approving, not really because I can read the code, but because I'm keen to get it shipped 😄.