Fix telemetry-server build: proper Docker context, Go 1.25, local module (#7247)

* fix(telemetry): make server build reproducible with proper context and deps

* Update telemetry/server/go.mod: go version

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* telemetry/server: optimize Dockerfile (organize cache deps, copy proto); run as non-root

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

telemetry/docker-compose.yml

@@ -2,7 +2,9 @@ version: '3.8'
 
 services:
   telemetry-server:
-    build: ./server
+    build:
+      context: ../
+      dockerfile: telemetry/server/Dockerfile
     ports:
       - "8080:8080"
     command: [