feat: award activity points for MMOCore profession XP

[JustinasLa]

Adds an optional profession: key on an activity, so a weekly goal can be
expressed as "gain 500 xp in Forager". Ships entries for crafter,
forager and herborist.

Notes

• Professions are MMOCore's, not RPCharacters'. RPCharacters only
  listens to MMOCore level-ups and mints its own separate profession-point
  currency, so the XP source here is MMOCore's PlayerExperienceGainEvent.
• Profession ids are normalised exactly as MMOCore normalises them
  (lowercase, _ and space to -). Without this, a future
  mining_expert.yml would silently never match the config key the docs
  tell you to write.
• MMOCore multiplies profession XP by boosters, so events carry fractional
  values. Flooring per event would under-count permanently (~9% at x1.1)
  and would never credit a profession tuned below 1 xp/action, so the
  remainder is carried per player per activity and evicted on quit.
• Entries ship commented out — on a server without MMOCore they would
  otherwise render as GUI rows permanently stuck at 0. Uncomment to enable.
• MythicLib is a second compile-only dependency: MMOCore's Profession
  implements a MythicLib interface, so javac cannot resolve getId()
  without it. Verified compile-only, nothing shaded into the output jar.

Blocked on

CI will fail its sha256sum -c step until these two jars are uploaded to
the JustinasLa/tfmc-deps v1 release under exactly these names:

• MMOCore-1.13.1.jar
• MythicLib-dist-1.7.1.jar

Hashes in libs/SHA256SUMS match the jars installed on the live server.

Verification

mvn -B clean package locally: BUILD SUCCESS, 78 tests, 0 failures.
Reviewed by code-reviewer (APPROVE, 0 findings after a fix round) and
security-specialist (PASS, 0 critical/high).

[JustinasLa]

Superseded by #10 — same commit without the attribution trailer.