refactor(openapi): inject file upload service

[hjlarry]

Summary

part of #39993

Stack: #41587
Depends on #41603.

• inject the shared FileService through application_services() instead of constructing it from Flask database globals in the OpenAPI controller
• preserve caller-derived tenant resolution and the existing @returns / FileResponse serialization contract
• order typed file-service exceptions before the generic ValueError fallback so their intended HTTP errors are reachable
• update generated OpenAPI Markdown and add focused controller coverage

Behavior changes

• oversized files now return 413 file_too_large instead of a generic 400 bad_request
• unsupported file types now return 415 unsupported_file_type instead of a generic 400 bad_request
• blocked extensions still return 400, now with file_extension_blocked instead of bad_request

[github-actions]

Pyrefly Type Coverage

Metric	Base	PR	Delta
Type coverage	62.10%	62.13%	+0.02%
Strict coverage	61.71%	61.73%	+0.02%
Typed symbols	43,469	43,494	+25
Untyped symbols	26,696	26,685	-11
Modules	3308	3309	+1

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.96%. Comparing base (4207d8b) to head (c62f3e8).

Additional details and impacted files

@@                   Coverage Diff                   @@
##           refactor/console-files   #41606   +/-   ##
=======================================================
  Coverage                   86.96%   86.96%           
=======================================================
  Files                        5322     5322           
  Lines                      306772   306771    -1     
  Branches                    61453    61453           
=======================================================
+ Hits                       266775   266786   +11     
+ Misses                      34704    34691   -13     
- Partials                     5293     5294    +1     

Flag	Coverage Δ
api	86.82% <100.00%> (+<0.01%)	⬆️

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