test: assert max commission rate in v6 to v7 upgrade test (#6538)

## Summary
- Add `validateMaxCommissionRate` helper that queries all validators and
asserts each validator's `max_rate >= 0.60` after the v7 upgrade
- Call it from `ValidatePostUpgrade` (used by `TestUpgradeLatest`) and
the v7 case in `validateParameters`
- Add `MaxCommissionRateV7 = "0.60"` constant

Closes #6529

## Test plan
- [ ] `make test-docker-e2e test=TestUpgradeLatest` passes with the new
max commission rate assertion

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: rootulp

test/docker-e2e/e2e_upgrade_test.go

@@ -28,6 +28,7 @@ import (
 const (
 	AppVersionV5 uint64 = 5
 	AppVersionV6 uint64 = 6
+	AppVersionV7 uint64 = 7
 
 	InflationRateV5 = "0.0536" // 5.36%
 	InflationRateV6 = "0.0267" // 2.67%
@@ -37,6 +38,9 @@ const (
 
 	MinCommissionRateV5 = "0.05" // 5%
 	MinCommissionRateV6 = "0.10" // 10%
+	MinCommissionRateV7 = "0.20" // 20%
+
+	MaxCommissionRateV7 = "0.60" // 60%
 
 	EvidenceMaxAgeV5Hours = 504
 	EvidenceMaxAgeV6Hours = 337
@@ -76,6 +80,10 @@ func (s *CelestiaTestSuite) TestAllUpgrades() {
 			baseAppVersion:   5,
 			targetAppVersion: 6,
 		},
+		{
+			baseAppVersion:   6,
+			targetAppVersion: 7,
+		},
 	}
 
 	for _, tc := range tt {
@@ -386,6 +394,12 @@ func (s *CelestiaTestSuite) validateParameters(ctx context.Context, node tastora
 		return
 	}
 
+	if appVersion == AppVersionV7 {
+		s.validateMinCommissionRate(ctx, node, MinCommissionRateV7, AppVersionV7)
+		s.validateMaxCommissionRate(ctx, node, MaxCommissionRateV7, AppVersionV7)
+		return
+	}
+
 	s.T().Fatalf("invalid app version: %d", appVersion)
 }
 
@@ -485,6 +499,48 @@ func (s *CelestiaTestSuite) validateMinCommissionRate(ctx context.Context, node
 	s.Require().True(diff.LTE(tolerance), "v%d min commission rate mismatch: expected %s, got %s, diff=%s", appVersion, expectedRate, minCommissionRateStr, diff.String())
 }
 
+// validateMaxCommissionRate queries all validators and validates that each
+// validator's max commission rate is at least the expected value.
+func (s *CelestiaTestSuite) validateMaxCommissionRate(ctx context.Context, node tastoratypes.ChainNode, expectedRate string, appVersion uint64) {
+	dcNode, ok := node.(*tastoradockertypes.ChainNode)
+	s.Require().True(ok, "node should be a docker chain node")
+
+	networkInfo, err := node.GetNetworkInfo(ctx)
+	s.Require().NoError(err, "failed to get network info from chain node")
+
+	rpcEndpoint := fmt.Sprintf("tcp://%s:26657", networkInfo.Internal.Hostname)
+	cmd := []string{"celestia-appd", "query", "staking", "validators", "--output", "json", "--node", rpcEndpoint}
+
+	stdout, stderr, err := dcNode.Exec(ctx, cmd, nil)
+	s.Require().NoError(err, "failed to query staking validators via CLI: stderr=%s", string(stderr))
+
+	var validatorsResp struct {
+		Validators []struct {
+			Commission struct {
+				CommissionRates struct {
+					MaxRate string `json:"max_rate"`
+				} `json:"commission_rates"`
+			} `json:"commission"`
+		} `json:"validators"`
+	}
+	err = json.Unmarshal(stdout, &validatorsResp)
+	s.Require().NoError(err, "failed to parse staking validators JSON response")
+	s.Require().NotEmpty(validatorsResp.Validators, "no validators found in response")
+
+	expectedDec, err := math.LegacyNewDecFromStr(expectedRate)
+	s.Require().NoError(err, "failed to parse expected max commission rate")
+
+	for i, val := range validatorsResp.Validators {
+		maxRateStr := val.Commission.CommissionRates.MaxRate
+		s.Require().NotEmpty(maxRateStr, "max_rate not found for validator %d", i)
+
+		actualDec, err := math.LegacyNewDecFromStr(maxRateStr)
+		s.Require().NoError(err, "failed to parse actual max commission rate for validator %d: %s", i, maxRateStr)
+
+		s.Require().True(actualDec.GTE(expectedDec), "v%d validator %d max commission rate too low: expected >= %s, got %s", appVersion, i, expectedRate, maxRateStr)
+	}
+}
+
 // validateEvidenceParams queries and validates both evidence max age duration and blocks using CLI
 func (s *CelestiaTestSuite) validateEvidenceParams(ctx context.Context, node tastoratypes.ChainNode, expectedHours int, expectedBlocks int, appVersion uint64) {
 	dcNode, ok := node.(*tastoradockertypes.ChainNode)