feat: carrier auto detect

[jmdevita]

Summary

Adds automatic carrier detection from tracking numbers, so the courier field is now optional
when calling add_parcel or edit_parcel.

• Uses regex patterns and checksum validation from
  jkeen/tracking_number_data (vendored JSON, no
  runtime API calls)
• Supports 11 carriers: UPS, FedEx (7 formats), USPS (4 formats), DHL (5 formats), Amazon,
  Canada Post, DPD, OnTrac, LaserShip, Landmark, Old Dominion
• 6 checksum algorithms: mod10, mod7, s10, luhn, sum_product, mod_37_36
• New detect_carrier service for testing detection in HA developer tools
• Backwards compatible — existing automations that pass courier explicitly are unaffected
• Adds HA <2025.12 compatibility for description_placeholders

New files

• carrier_detection.py — core detection module
• tracking_data/*.json — 12 vendored carrier pattern files
• tests/test_carrier_detection.py — 247 tests using jkeen's own test vectors

[jmdevita]

ping @PineappleEmperor if you have a moment, it may look like a massive change, but it's really just using https://github.com/jkeen/tracking_number_data as the source of truth for some auto-detection of carriers.

[PineappleEmperor]

Hallo! Apologies for being AWOL! Looks good to me! We could consider releasing these as betas to make it easier to test/review? How do you want to package all of these PRs into a new version?

[jmdevita]

@PineappleEmperor Good idea, and I'm not sure yet.. I can figure this out this weekend unless you have any ideas!

[jmdevita]

@PineappleEmperor just pushed as a v1.8.0 pre-release, it absorbs a few other PRs as well. I'll test on my main HA instance but things are looking good!

[PineappleEmperor]

@jmdevita sorry again! I'm rammed at the minute! I've installed the beta on my main HA and have run a few tests - looks good to me!

I could see us getting requests for more automatically recognised tracking numbers, depending on how popular the feature is?

Do you want to squash and merge when you're ready to release it fully? :)