feat(carriers): slice 3 regional, local, and Alaska carriers

[Orinks]

Carrier slice 3 data, per the approved plan (docs/carrier-slice3-plan.md). This folds in the plan PR #257 (its three plan commits are the first three here), which is closed as superseded.

Carriers (24)

Tier	Count	Carriers
National	3	Northstar, Great Lakes Training, Summit Value (unchanged)
Regional	18	17 lower-48 (Prairie Link plus 16 new), and Chatanika Freight Lines in Alaska
Local	3	Des Plaines River Cartage (Chicago, Gary, Aurora), Basin Harbor Drayage (Los Angeles, Riverside), Knik Arm Cartage (Anchorage)

• Names are final. Catawba Ridge Transport became Meherrin Transport (meherrin_transport). The plan's sections 1, 2, 10, 11 and 12 are updated.
• The Tehachapi wording no longer implies CA-58 is the LA-Fresno lane.
• Loonwater Regional has its Green Bay terminal.
• Tier bands:
  • regional: hires within 250 air mi, run band 150-600;
  • local: hires within 50 air mi, run band 25-150.
  • Only the band maximum is applied today; the minimum waits for slice 4, so no player text promises a minimum.
• Every new carrier has a spoken lane_area and a generated start option. That opens Alaska home cities in the picker; BC and YT stay closed.

Fallback when a carrier lets a driver go (plan section 5)

A driver is let go by check_carrier_termination, a debt termination, or a low-reputation repossession. The fallback is chosen from the driver's home city (home_city, else home_terminal_city, else current_city):

1. The nearest regional or local that hires there, never the carrier that let the driver go.
2. Otherwise Great Lakes Training, which hires anywhere in the lower 48.
3. Otherwise, no carrier.

Details:

• A repossession has no carrier doing the firing, so it skips the "never the firing carrier" filter, as the plan says.
• The new carrier keeps the driver on sufferance (DrivingRecord.sufferance_carrier_key). The same record can't end that job again, and debt stops at the ceiling, the same way it does at Great Lakes Training.
• An Alaska driver never goes to a lower-48 carrier.

Driver with no carrier. The save stores an empty carrier_key and carrier_name.

• The terminal's arrival line says "You have no carrier right now. Choose Apply to a carrier to take a seat."
• Apply to a carrier replaces the Dispatch board item.
  • It lists carriers that hire in the home city, never the one that let the driver go.
  • If none hire there, it lists carriers with a terminal in the same state; each of those says it moves the driver's home there.
  • Example: "Knik Arm Cartage: local carrier, hires into its Anchorage terminal, moves your home to Anchorage".
• Picking a carrier starts the driver at that terminal, kept on sufferance if their record would otherwise end the job.
• Opening the dispatch board with no carrier says why there is none.

Tests

• 625/625 lower-48 cities are hired into by a regional and offered in the picker.
• Every Alaska city is offered, and only Alaska carriers hire there; BC and YT are not offered.
• For every Alaska home and every firing carrier, no lower-48 carrier appears in the fallback or in the openings.
• The fallback rule: never the firing carrier, nearest regional or local first; Fairbanks let go by Chatanika ends up with no carrier, with Knik Arm offered as a move. These run through both the profile and the terminal menu.
• Tier bands, unique names, and terminal yard pins.
• Fairbanks is the one terminal city with no world company_yard/terminal pin. It is named in the test with its reason and has a ROADMAP row.

Docs

• ROADMAP:
  • the regionals and coverage-test rows are checked off;
  • new rows for Loonwater's 636 mi span and the Fairbanks yard pin;
  • the orinks.net export row now covers the new carrierLabels and the empty carrier fields.
• CHANGELOG bullet added.
• profile_integrity_invariants.json is regenerated (carrierLabels).