feat: align init module discovery with registry (backlog-core-01)

[djm81]

Description

Aligns specfact init module discovery with the registry: init now uses discover_all_package_metadata() so --list-modules, --enable-module, and --disable-module see the same roots as the CLI (built-in + workspace-level modules/ + SPECFACT_MODULES_ROOTS). Extends backlog-core-01 with init-module-discovery-alignment; bumps version to 0.34.0.

Fixes #116

Contract References: Init commands use existing contracts; discovery uses discover_all_package_metadata() from registry.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 📚 Documentation update

Contract-First Testing Evidence

Contract Validation

• Runtime contracts existing on public APIs
• Type checking enforced
• Contract validation: hatch run contract-test-contracts ✅
• Scenario tests: hatch run contract-test-scenarios ✅

Test Execution

• Contract validation ✅
• Scenario tests ✅
• Full test suite (smart-test / contract-test) ✅

How Has This Been Tested?

• Contract validation passes
• Scenario tests cover init list/enable/disable with workspace modules
• All existing tests still pass

Test Environment

• Python 3.11+
• Linux

Checklist

• Code follows style guidelines (ruff format, isort)
• Self-review done
• Corresponding OpenSpec/tasks/CHANGELOG updated
• All tests pass locally
• Tests added for init discovery alignment (test_init_module_lifecycle_ux.py)

Quality Gates Status

• Type checking ✅ (hatch run type-check)
• Linting ✅ (hatch run lint)
• Contract validation ✅ (hatch run contract-test)
• Scenario tests ✅