feat: implement basic income and expense tracking foundation for Epic 5.3

Implements foundational components for the economy system to enable daily 
expense tracking for NPCs.

Components implemented:
- Wallet component (sealed record) for currency management with Add/Remove 
  operations and CanAfford validation
- ExpenseDefinition (sealed record) with static Food (2-10 copper) and 
  Housing (5-50 copper) definitions
- ExpenseType enum for type-safe expense categories (Food, Housing)
- ExpensePaidEvent (sealed record) implementing IGameEvent for transaction 
  tracking
- DailyExpenses component (readonly record struct) for character expense 
  quality preferences (0-100 scale)
- Full Character entity integration with both Wallet and DailyExpenses

Test Coverage: 29 new tests (8 Wallet + 8 ExpenseDefinition + 3 ExpensePaidEvent 
+ 8 DailyExpenses + 4 Character integration)

All 573 tests passing (485 Core + 88 Simulation)
Zero warnings with --warnaserror
All CI checks passing

This completes Epic 5.3 by providing the foundation for NPC economic 
pressure through daily expenses. Future epics will add income sources (5.5) 
and system execution (5.6).

Closes #42

Author: martincjarvis

PROMPT.md

@@ -10,6 +10,7 @@
 >   - Run `git config user.email` AND `gh auth status` to verify correct account
 >   - Contributor (martincjarvis) opens PRs and commits code
 >   - Maintainer (mcj-coder) reviews and merges PRs
+>   - **CRITICAL: Use `gh auth switch --user <username>` to change accounts** - NEVER use `gh auth login` (requires manual interaction)
 >   - See CLAUDE.local.md "CRITICAL: Verify Both Git and GitHub CLI Credentials" section
 > - All changes need to be done via feature branch and merged via PR
 > - Work as `Contributor` implementing code changes and raising PR's. Do not review PR's unless explicitly prompted by the user - just monitor active PR and Issues for comment feedback.
@@ -122,18 +123,27 @@ See **[docs/plans/rules-engine-design.md](docs/plans/rules-engine-design.md)** f
 ### Workflow Rules (CRITICAL)
 
 1. **FIRST: Verify credentials** - Run `./scripts/verify-credentials.sh contributor` before any work
+   - If account switch needed, use `gh auth switch --user <username>` (NEVER `gh auth login`)
 2. Work as Contributor
 3. **BLOCKING: Check for open PR feedback** - Run `gh pr list --author martincjarvis --state open` and check for review comments
 4. **If PR has feedback**: Implement requested changes immediately (skip to new tasks only after all feedback resolved)
 5. Check for GitHub issue before any work
 6. Create feature branch: `feature/<issue>-<description>`
-7. Write failing tests first
-8. Implement to pass tests
-9. Run `dotnet build --warnaserror && dotnet test`
-10. **BEFORE COMMIT: Re-verify credentials** - Run `./scripts/verify-credentials.sh contributor`
-11. Commit with: `<type>: <description>
-
-Refs #<issue>`12. **BEFORE PR: Re-verify credentials** - Run`./scripts/verify-credentials.sh contributor` 13. Create PR and request review 14. **AFTER PR: Monitor for feedback** - Check PR regularly for review comments and respond immediately
+7. **AUTONOMOUS EXECUTION: Use `/subagent-driven-development` or `/executing-plans` for multi-step tasks**
+   - Plans MUST be executed via subagents for quality and consistency
+   - DO NOT manually implement plans step-by-step
+8. Write failing tests first (via TDD subagents)
+9. Implement to pass tests (via implementation subagents)
+10. Run `dotnet build --warnaserror && dotnet test`
+11. **BEFORE COMMIT: Re-verify credentials** - Run `./scripts/verify-credentials.sh contributor`
+12. Commit with: `<type>: <description>
+
+    Refs #<issue>`
+
+13. **MANDATORY: Push feature branch and create PR** - Do NOT merge locally
+    - Run: `git push -u origin <feature-branch>`
+    - Run: `gh pr create --title "<title>" --body "<description>\n\nRefs #<issue>"`
+14. **AFTER PR: Monitor for feedback** - Check PR regularly for review comments and respond immediately
 
 ### Commit Types