Serialize msa yarn modules to fix intermittent `tsc: not found` under -T

Under `mvn -T<n>` with the three yarn-using modules (ui-ngx,
msa/web-ui, msa/js-executor), concurrent yarn 1.x processes contend
on the shared `~/.cache/yarn`. The `--mutex network` flag was applied
only to `yarn install`, so `yarn run pkg` could overlap with another
module's install. Intermittent failures observed on CI:
`/bin/sh: 1: tsc: not found` during `yarn run pkg`, caused by
incomplete typescript extraction into per-module node_modules.

Fix at two layers:

1. Maven reactor chain (primary): add reactor-only pom <dependency>
   entries (type=pom, scope=provided, wildcard exclusions) to form
       ui-ngx -> msa/web-ui -> msa/js-executor
   so the MultiThreadedBuilder schedules them strictly serial,
   regardless of -T thread count. msa/web-ui already had a real
   dependency on ui-ngx; only one new fake link was needed.

2. Yarn-level mutex (defense in depth): add `--mutex network` to
   `yarn run pkg` (msa/web-ui, msa/js-executor) and
   `yarn run build:prod` (ui-ngx), so single-module builds outside the
   reactor chain (`mvn -pl msa/<module>`) still serialize against any
   other yarn process on the agent.

Comment in msa/pom.xml updated: the previous "Modules order is
important..." note was misleading - module order in the reactor does
not enforce serialization under -T; the dependency edges do.

msa/js-executor/pom.xml

@@ -52,6 +52,29 @@
             <type>exe</type>
             <scope>provided</scope>
         </dependency>
+        <!--
+            Reactor-only ordering dep (NOT a real classpath dependency).
+            Forces `mvn -T<n>` to serialize this module after web-ui so that
+            no two `yarn install` / `yarn run pkg` invocations can overlap on
+            the same agent. Concurrent yarn 1.x processes share ~/.cache/yarn
+            and have intermittently produced `tsc: not found` failures during
+            yarn pkg (incomplete typescript extraction in node_modules).
+            The chain is: ui-ngx -> msa/web-ui -> msa/js-executor.
+            type=pom + provided + wildcard exclusions keep nothing on the classpath.
+        -->
+        <dependency>
+            <groupId>org.thingsboard.msa</groupId>
+            <artifactId>web-ui</artifactId>
+            <version>${project.version}</version>
+            <type>pom</type>
+            <scope>provided</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>*</groupId>
+                    <artifactId>*</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
     </dependencies>
 
     <build>
@@ -90,7 +113,7 @@
                         </goals>
                         <phase>compile</phase>
                         <configuration>
-                            <arguments>run pkg</arguments>
+                            <arguments>--mutex network run pkg</arguments>
                         </configuration>
                     </execution>
                 </executions>

msa/pom.xml

@@ -44,7 +44,16 @@
     </properties>
 
     <modules>
-        <!--Modules order is important to speedup parallel build and avoid yarn pgk parallel execution-->
+        <!--
+            Module order below is informational only. Yarn-using modules
+            (web-ui, js-executor) are serialized via reactor-only
+            <dependency> entries in their own poms, forming the chain
+            ui-ngx -> web-ui -> js-executor. This prevents
+            concurrent yarn install / yarn run pkg invocations under `mvn -T<n>`,
+            which previously caused intermittent `tsc: not found` failures
+            (incomplete typescript extraction in node_modules from racing
+            yarn 1.x processes against the shared ~/.cache/yarn).
+        -->
         <module>tb</module>
         <module>web-ui</module>
         <module>vc-executor</module>

msa/web-ui/pom.xml

@@ -99,7 +99,7 @@
                         </goals>
                         <phase>compile</phase>
                         <configuration>
-                            <arguments>run pkg</arguments>
+                            <arguments>--mutex network run pkg</arguments>
                         </configuration>
                     </execution>
                 </executions>

ui-ngx/pom.xml

@@ -106,7 +106,7 @@
                                     <goal>yarn</goal>
                                 </goals>
                                 <configuration>
-                                    <arguments>run build:prod</arguments>
+                                    <arguments>--mutex network run build:prod</arguments>
                                 </configuration>
                             </execution>
                         </executions>