fix: attunement system spec-vs-code discrepancies (issue #331)

- Fix conversion rate level scaling from linear (1+level*0.5) to exponential (1.5^(level-1)) in conversion-rates.ts
- Fix getAttunementLevelMultiplier formula to match spec §4.3
- Add level-up logging in attunementStore.ts via combat store addActivityLog
- Clarify getAttunementConversionRate returns flat base rate (level scaling applied separately)
- Update spec §8 to describe time-based puzzle room system matching code implementation
- Add 17 regression tests verifying exponential scaling, base rate behavior, and spec table values

docs/specs/attunements/attunement-system-spec.md

@@ -295,8 +295,12 @@ per-attunement variants:
 | `hybrid_enchanter_invoker` | Dual attunement challenge |
 | `hybrid_fabricator_invoker` | Dual attunement challenge |
 
-Progress scales at 1.5–2% per tick base, with attunement bonus of 2.5–3% per
-relevant attunement level.
+**Time-based progression system:** Each puzzle room has a base time requirement
+that varies by floor range (4h for floors 1–20, 8h for 21–50, 16h for 51–100,
+24h for 101+). Each relevant attunement reduces the total time needed, up to
+a maximum 90% reduction shared across all relevant attunements. Progress
+accumulates at `HOURS_PER_TICK` (0.04h) per tick. The room completes when
+`puzzleProgress >= puzzleRequired`.
 
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