Make migration part of the agentic app (temporarily)

[timfdev]

Closes #1085
Closes #1088

[codspeed-hq]

CodSpeed Performance Report

Merging #1096 will not alter performance

_{Comparing optional-migration (8a42d21) with main (37fe84f)}

Summary

✅ 13 untouched

[codecov]

Codecov Report

❌ Patch coverage is 68.65672% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.42%. Comparing base (37fe84f) to head (8a42d21).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
orchestrator/agentic_app.py	43.47%	11 Missing and 2 partials ⚠️
orchestrator/search/llm_migration.py	89.65%	3 Missing ⚠️
orchestrator/__init__.py	66.66%	0 Missing and 1 partial ⚠️
orchestrator/api/api_v1/api.py	0.00%	0 Missing and 1 partial ⚠️
orchestrator/cli/main.py	83.33%	0 Missing and 1 partial ⚠️
orchestrator/search/indexing/indexer.py	0.00%	1 Missing ⚠️
orchestrator/workflows/steps.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1096      +/-   ##
==========================================
+ Coverage   80.31%   80.42%   +0.10%     
==========================================
  Files         261      262       +1     
  Lines       12695    12729      +34     
  Branches     1243     1244       +1     
==========================================
+ Hits        10196    10237      +41     
+ Misses       2221     2212       -9     
- Partials      278      280       +2     

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