fix: harden gRPC route and assignment Broker validation

[Aias00]

Summary

• Skip invalid route entries that lack Broker data while retaining valid queues during gRPC route lookup.
• Reject assignment responses safely when no master Broker is available.

Validation

mvn -q -pl proxy -am -Dtest=RouteActivityTest -DfailIfNoTests=false test

Closes #10770
Closes #10768

[Copilot]

Pull request overview

This PR hardens Proxy gRPC RouteActivity#queryAssignment against malformed/partial route metadata by skipping queue rows that don’t have a master broker entry, avoiding exceptional failures during protobuf MessageQueue construction and instead returning the existing controlled FORBIDDEN response when no valid assignments remain.

Changes:

• Skip queue rows where brokerIdMap.get(MixAll.MASTER_ID) returns null in RouteActivity#queryAssignment.
• Add a regression test covering route metadata that only contains non-master broker IDs.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
proxy/src/main/java/org/apache/rocketmq/proxy/grpc/v2/route/RouteActivity.java	Skips queue rows lacking a master broker to prevent null broker usage when building assignments.
proxy/src/test/java/org/apache/rocketmq/proxy/grpc/v2/route/RouteActivityTest.java	Adds coverage for the “missing master broker” route-metadata scenario, asserting a controlled FORBIDDEN response with no assignments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.51%. Comparing base (293f588) to head (2530042).

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10771      +/-   ##
=============================================
- Coverage      48.62%   48.51%   -0.11%     
+ Complexity     13692    13654      -38     
=============================================
  Files           1381     1381              
  Lines         101464   101466       +2     
  Branches       13187    13188       +1     
=============================================
- Hits           49337    49228     -109     
- Misses         46142    46226      +84     
- Partials        5985     6012      +27     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[RockteMQ-AI]

Review by github-manager-bot

Summary

Adds null check for broker after brokerIdMap.get(MixAll.MASTER_ID) in DefaultConsumerAssignor.queryAssignment(), preventing NullPointerException when the master broker is missing from the route result.

Findings

• [Info] The fix is correct and minimal. Returning a FORBIDDEN result when the master broker is unavailable is the right behavior — the client should not proceed with assignment from an incomplete route.
• [Info] Test coverage verifies that a missing master broker results in FORBIDDEN with no assignments.

Suggestions

• None. Clean, targeted fix.

LGTM.

---

Automated review by github-manager-bot

[RockteMQ-AI]

Summary

Defensive fix with proper validation and test coverage. LGTM.

---

Automated review by github-manager-bot