#18730: fix(plugins): suppress duplicate ID warnings for intentional origin overrides

## Summary Fixes false-positive duplicate plugin ID warnings that appeared when workspace/global extensions intentionally override bundled plugins. The system now only warns when true conflicts occur (same-precedence duplicates). ## Problem Users saw warnings like: ``` duplicate plugin id detected; later plugin may be overridden (workspace/matrix/index.ts) ``` Even though this was expected behavior — workspace/global extensions intentionally override bundled plugins based on precedence. ## Solution Modified `src/plugins/manifest-registry.ts` to distinguish between: - **Intentional overrides (different precedence)**: No warning - Example: bundled "matrix" + workspace "matrix" = workspace wins ✅ - **True conflicts (same precedence)**: Warning issued - Example: global "matrix" + global "matrix" = conflict ⚠️ Precedence ranking: `config > workspace > global > bundled` ## Changes ### Code Changes **File**: `src/plugins/manifest-registry.ts` (lines 232-246) Added precedence-aware duplicate detection: ```typescript const samePrecedence = PLUGIN_ORIGIN_RANK[candidate.origin] === PLUGIN_ORIGIN_RANK[existing.candidate.origin]; if (samePrecedence) { diagnostics.push({...}); } ``` ### Test Changes **File**: `src/plugins/manifest-registry.test.ts` - Updated test: different-precedence (bundled + global) → expects 0 warnings - Added test: same-precedence (global + global) → expects 1 warning ## Testing Strategy | Scenario | Origins | Expected Warning | |----------|---------|------------------| | Different precedence | bundled + global | ❌ No warning | | Same precedence | global + global | ✅ Warn | | Same physical dir | symlinked paths | ❌ No warning | | Identical rootDir | same path, different source | ❌ No warning | ## Validation - [x] TypeScript compilation passes - [x] Logic verified against precedence: `config(0) > workspace(1) > global(2) > bundled(3)` - [x] Both test scenarios cover the new behavior ⚠️ **Note**: Full `pnpm test` couldn't run due to vendor/a2ui submodule dependency requiring native build tools not available in sandbox. However: - Code syntax validated - Logic matches Greptile-reviewed PR #18418 approach - Tests cover both pass/fail cases ## Related Closes #18330 --- ## 🤖 AI Assistance Disclosure This PR is **AI-assisted** using Claude via OpenClaw. - **Testing level**: Logic validated, TypeScript syntax checked, test cases written. Full build/test blocked by canvas dependency. - **I understand what the code does**: The change adds a precedence check before emitting duplicate warnings. Higher-precedence origins (workspace, global) intentionally override lower ones (bundled), so warnings should only fire for same-precedence conflicts. - **Prompts/session logs**: Multi-step implementation covering source analysis, code changes, and test updates.