feat(python-notebook-migration): add notebook-migration-service microservice in backend

[zyratlo]

What changes were proposed in this PR?

Introduces the microservice that mediates between Texera and the JupyterLab docker stack landed in migration-tool-jupyter-docker. Adds a new SBT subproject notebook-migration-service plus shared config and a frontend dev-proxy route.

New SBT subproject notebook-migration-service/:

• build.sbt and project/build.properties — module SBT setup; module depends on the existing Auth, Config, and DAO projects
• src/main/scala/.../NotebookMigrationService.scala — Dropwizard Application entry point; sets Jersey URL pattern to /api/*, registers the resource class, initializes the shared SQL connection via
  SqlServer.initConnection(StorageConfig.jdbcUrl, …), and wires in RequestLoggingFilter.
• src/main/scala/.../NotebookMigrationServiceConfiguration.scala — Dropwizard Configuration subclass.
• src/main/scala/.../resource/NotebookMigrationResource.scala — five REST endpoints under /notebook-migration:
  • GET /get-jupyter-url — health-checks the Jupyter container and returns its base URL.
  • GET /get-jupyter-iframe-url — returns the iframe-ready URL for notebook.ipynb.
  • POST /set-notebook — receives a notebook JSON, PUTs it into JupyterLab via its /api/contents/work/{name} API.
  • POST /store-notebook-and-mapping — persists a notebook + workflow-notebook mapping into Postgres in a single transaction (writes to the notebook and workflow_notebook_mapping tables added by migration-tool-database-tables).
  • POST /fetch-notebook-and-mapping — returns the most recent notebook + mapping for a given (wid, vid).
• src/main/resources/logback.xml — logging config.
• src/main/resources/notebook-migration-service-web-config.yaml — Dropwizard server config (HTTP port 9098, DB connection refs).

Root build wiring:

• build.sbt — declares the new NotebookMigrationService SBT subproject and adds it to the TexeraProject aggregation.

Shared config:

• common/config/src/main/resources/storage.conf — new jupyter { url = "http://localhost:9100" } block, overridable via STORAGE_JUPYTER_URL.
• common/config/src/main/scala/.../StorageConfig.scala — adds the jupyterURL accessor.

Frontend dev proxy:

• frontend/proxy.config.json — routes /api/notebook-migration/* to http://localhost:9098.

Any related issues, documentation, discussions?

Closes #5257
Parent issue #4301

• Hard dependency: must be merged after migration-tool-database-tables feat(python-notebook-migration): add database tables for Notebook Migration tool #5055 — the resource imports jOOQ-generated Notebook / WorkflowNotebookMapping classes that only exist once the schema PR is merged.
• Soft dependency: the JupyterLab container from migration-tool-jupyter-docker is what StorageConfig.jupyterURL points to. Without it running, the Jupyter-related endpoints return a 500 with "Cannot connect to Jupyter server". Service still starts and the DB-persistence endpoints work in isolation.

How was this PR tested?

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Claude Opus 4.7)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.95%. Comparing base (d8c254c) to head (baea89a).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5258      +/-   ##
============================================
- Coverage     48.95%   48.95%   -0.01%     
  Complexity     2377     2377              
============================================
  Files          1048     1048              
  Lines         40270    40270              
  Branches       4272     4272              
============================================
- Hits          19714    19713       -1     
  Misses        19402    19402              
- Partials       1154     1155       +1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	39.53% <ø> (ø)
agent-service	33.76% <ø> (ø)		Carriedforward from 0c3af5e
amber	51.57% <ø> (ø)		Carriedforward from 0c3af5e
computing-unit-managing-service	0.00% <ø> (ø)
config-service	0.00% <ø> (ø)
file-service	37.99% <ø> (ø)
frontend	40.64% <ø> (ø)
python	90.79% <ø> (ø)		Carriedforward from 0c3af5e
workflow-compiling-service	56.81% <ø> (ø)

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