feat(FN-3891): expose verification auto-fix retries in merge settings

- Add verificationFixRetries input to SettingsModal merge section with 0-3 clamping

- Default to 3 retries with proper empty-value fallback to undefined

- Cover edge cases with SettingsModal tests: default, valid values, clamping, clearing

- Add patch changeset for @runfusion/fusion

- Update settings-reference.md with revised default and description

Fusion-Task-Id: FN-3891

docs/settings-reference.md

@@ -209,7 +209,7 @@ Defaults from `DEFAULT_PROJECT_SETTINGS`; key scope from `PROJECT_SETTINGS_KEYS`
 | `mergerAutostashMaxAgeHours` | `number` | `24` | Maximum autostash age in hours before startup/periodic stale-stash sweep drops `fusion-merger-autostash:*` leftovers (minimum `1`). |
 | `strictScopeEnforcement` | `boolean` | `false` | Block merges on out-of-scope file changes. |
 | `buildRetryCount` | `number` | `0` | Build retry attempts during merge. |
-| `verificationFixRetries` | `number` | `2` | Auto-fix retry attempts when verification fails during merge. |
+| `verificationFixRetries` | `number` | `3` | In-merge auto-fix retry attempts after deterministic test/build verification failures (0-3). |
 | `buildTimeoutMs` | `number` | `300000` | Build timeout in milliseconds (5 minutes). |
 | `requirePlanApproval` | `boolean` | `false` | Require manual approval before planning → todo. |
 | `agentProvisioning` | `{ approvalMode?: "always" \| "trusted-only" \| "never"; trustedRoles?: string[]; trustedAgentIds?: string[]; alwaysApproveDelete?: boolean }` | `{}` | Approval policy for `fn_agent_create`/`fn_agent_delete` (`approvalMode` default `trusted-only`, delete approvals default on via `alwaysApproveDelete: true`). |