Phase 5: soft gates instead of guardian flags, shoulder passives

Adrian (2026-10-31): HMs abilities stay open; the ones that get around
zone hazards get soft gates (materials or a high-level Pokemon, never
flags; gifted Pokemon and materials count the same); party passives from
shoulder Pokemon; Cobblebase skills and the Power Block move to soft
gates too.

- Gates: a zone gate passes at the top of the zone's band or while the
  Pokemon holds the zone's material (or a harder zone's). Cobblebase
  skills check the pastured Pokemon and tell the owner once what it needs.
- Progress record, guardian unlock messages, the Power Block placement
  gate and /cobblesurvival progress removed; the Power Block's recipe
  already needs Jungle redstone.
- HmsGate: switches off gated HMs auras (Flash, Dive, Mist, Rock Climb,
  Magnet Rise, Lucky Chant, Lava Plume) whose Pokemon doesn't pass.
- ShoulderPassives: type-based effects from shoulder Pokemon, hazard
  ones (warmth, frigidness, water breathing, night vision) gated.
- Self-tests for all of it; docs, balance table, Phase 5 checklist.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/checklists/phase-4.md

@@ -24,6 +24,8 @@ The new template is the save folder "Cobblemon Survival Island (Phase 4)"; the w
 
 ## Base jobs and power (after the answers)
 
+**Superseded 2026-10-31:** the guardian flags below were replaced by soft gates (`docs/checklists/phase-5.md`); `/cobblesurvival progress` no longer exists.
+
 - **Cobblebase**, with each of its skills unlocked by beating a zone's Alpha guardian (table in `docs/balance.md`, data in `datapacks/core/data/cobblesurvival/progression_gates/base.json`). Automated: `gates_cover_every_cobblebase_skill`, `cobblebase_skills_wait_for_guardians`, and the guardian test checks that a win counts.
 - **Poke Power**: the Power Block can only be placed after the Verdant Jungle guardian. Automated: `power_block_waits_for_guardian`.