[group] Cross-repo impact analysis via repository groups

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to GitNexus will be documented in this file.
 
 ## [Unreleased]
 
+### Added
+- Cross-repo impact analysis (`group_impact` tool and CLI command)
+- Bridge.lbug storage: contract registry stored in LadybugDB instead of `contracts.json`
+- gRPC canonical ID normalization: proto-aware extraction with wildcard matching
+- Backward compatibility: automatic `contracts.json` fallback with deprecation warning
+
 ### Changed
 - Migrated from KuzuDB to LadybugDB v0.15 (`@ladybugdb/core`, `@ladybugdb/wasm-core`)
 - Renamed all internal paths from `kuzu` to `lbug` (storage: `.gitnexus/kuzu` → `.gitnexus/lbug`)

README.md

@@ -214,13 +214,14 @@ gitnexus group remove <name> <repo> # Remove a repo from a group
 gitnexus group list [name]       # List groups, or show one group's config
 gitnexus group sync <name>       # Extract contracts and match across repos/services
 gitnexus group contracts <name>  # Inspect extracted contracts and cross-links
+gitnexus group impact <name>     # Cross-repo blast radius analysis
 gitnexus group query <name> <q>  # Search execution flows across all repos in a group
 gitnexus group status <name>     # Check staleness of repos in a group
 ```
 
 ### What Your AI Agent Gets
 
-**16 tools** exposed via MCP (11 per-repo + 5 group):
+**17 tools** exposed via MCP (11 per-repo + 6 group):
 
 | Tool               | What It Does                                                      | `repo` Param |
 | ------------------ | ----------------------------------------------------------------- | -------------- |
@@ -234,11 +235,14 @@ gitnexus group status <name>     # Check staleness of repos in a group
 | `group_list`     | List configured repository groups                                 | —             |
 | `group_sync`     | Extract contracts and match across repos/services                 | —             |
 | `group_contracts`| Inspect extracted contracts and cross-links                       | —             |
+| `group_impact`   | Cross-repo blast radius analysis                                  | —             |
 | `group_query`    | Search execution flows across all repos in a group                | —             |
 | `group_status`   | Check staleness of repos in a group                               | —             |
 
 > When only one repo is indexed, the `repo` parameter is optional. With multiple repos, specify which one: `query({query: "auth", repo: "my-app"})`.
 
+> **Storage migration:** Group contract data is now stored in `bridge.lbug` (LadybugDB) instead of `contracts.json`. Existing groups with `contracts.json` are supported via automatic fallback with a deprecation warning. Run `gitnexus group sync <name>` to migrate.
+
 **Resources** for instant context:
 
 | Resource                                  | Purpose                                              |

docs/superpowers/plans/2026-04-02-pr626-high-fixes.md

@@ -1,5 +1,7 @@
 # PR #626 HIGH-Priority Fixes Implementation Plan
 
+> **Historical:** This plan was executed for PR #626. Contract storage has since migrated from `contracts.json` to `bridge.lbug`. See `2026-04-04-bridge-lbug-grpc-normalization.md` for the current plan.
+
 > **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
 
 **Goal:** Fix 4 HIGH-priority issues from PR #626 code review before merge.