Remove Workspace monthly limit and max cents fields

[BrewingCoder]

Parent: #25 — Remove all SaaS billing code

Depends on: #28 (pricing removal)

What to Remove from Workspace struct

Monthly Limits (6 fields)

Field	Line
MonthlySessionLimit	278
MonthlyMembersLimit	279
MonthlyErrorsLimit	280
MonthlyLogsLimit	281
MonthlyTracesLimit	282
MonthlyMetricsLimit	283

Max Cents (5 fields)

Field	Line
SessionsMaxCents	289
ErrorsMaxCents	290
LogsMaxCents	291
TracesMaxCents	292
MetricsMaxCents	293

Callers

File	Line	Usage
private-graph/graph/resolver.go	504-513	All Monthly*Limit fields mapped to response
private-graph/graph/resolver.go	518, 504, 506, 525, 527	All *MaxCents fields mapped
private-graph/graph/schema.resolvers.go	1287-1295	*MaxCents assigned in mutation
private-graph/graph/schema.resolvers.go	6469-6472	GetLimitAmount calls with *MaxCents
private-graph/graph/generated/generated.go	11829-11833, 94746	GraphQL complexity + field resolvers
public-graph/graph/resolver_test.go	600, 611	Test data

Also in Organization struct: MonthlySessionLimit at line 249

Migration Required

• Add DB migration to drop 11 columns from workspaces table
• Drop monthly_session_limit from organizations table

Test Plan

• Remove fields from Workspace and Organization structs
• Update resolver mappings (return nil/unlimited)
• Update GraphQL schema
• Regenerate: make private-gen + yarn codegen
• Add column-drop migration
• Verify build + tests

🤖 Generated with Claude Code

[github-actions]

AI Triage: Remove SaaS billing-related fields (monthly limits and max cents) from Workspace and Organization structs as part of billing code removal.

Labels applied: area:backend, tech-debt, component:database, billing-removal, priority:medium