[Feature]: [P2] Route inspector advice through a GameRules gate (Classic = cause only, Modern = cause + fix) and reconcile verdict framings

Bundles the recurring "fold into the holistic inspector-advice pass" deferrals from the #400 "Main gripe", pricing-split (#299), weekend-patronage-curve (#398), and commercial-demand-pools (#393) reviews, folded from the deferral inbox by #545. No holistic-advice row existed; the #400 review explicitly said to scope it as its own story.

• Classic shows fix advice, but the GDD reserves advice for Modern (medium). GRIPE_TEXT in facilityDiagnostics.ts bakes the fix into the line ("Add cars or a parallel shaft", etc.) in both modes, and the existing Access/W1/W3 inspector lines already embed advice with no mode gate. Mode-gating only the new line would be inconsistent, so the right move is one pass routing ALL inspector advice through a GameRules gate (Classic = cause only, Modern = cause + fix).
• Weekend "booming/quiet" verdict skews with the calendar (from #398). patronageYest folds in weekendMult but the verdict baseline is weekend-agnostic, so a venue can tip between "booming"/"very few" purely from the day of week. Fix: a weekend-aware baseline (multiply by rules.weekendMultiplier(kind, isWeekend)) or a disclosure line.
• Modern under-served advice vs a venue's own red verdict can read as tension (from #393 Phase C). The tower-level "another venue would still sell" can co-show with a venue's own poor-placement verdict; reconcile the venue-level vs tower-level framings here.
• Demand-% display rounds while the advice keys on raw share (from #393 Phase C). A venue in [0.995, 1) reads "100% of capacity" yet withholds the under-served nudge (and the [0.495, 0.5) mirror). Bounded to a 0.5% band, cosmetic; reconcile display and threshold off the same number when this pass runs.

Gameplay-facing (/gds-code-review). P2 driver is the Classic-vs-Modern advice gate (a GDD-intent divergence).

Tracked as backlog row inspector-advice-mode-gate; folded from the deferral inbox by #545.

Start in facilityDiagnostics.ts at GRIPE_TEXT and trace the existing Access/W1/W3 inspector advice, then locate the GameRules access for mode and weekend behavior. Review patronageYest, weekendMultiplier, the demand share display, and the venue- versus tower-level verdicts. Done means Classic shows causes only, Modern shows causes plus fixes, weekend verdicts use a consistent baseline, and displayed thresholds match advice.