feat(data-collection): configurable stack-frame variables and context lines

[ericapisani]

Part of the data_collection split — depends on #6676 (foundation).

Makes stack-frame variable inclusion and source-context line count read from the resolved DataCollection. Legacy mode preserves the current 5-line / include_local_variables behavior.

[github-actions]

Codecov Results 📊

✅ 90550 passed | ⏭️ 6240 skipped | Total: 96790 | Pass Rate: 93.55% | Execution Time: 319m 6s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +334
Passed Tests	📈 +399
Failed Tests	—
Skipped Tests	📉 -65

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2428 uncovered lines.
❌ Project coverage is 89.89%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    89.92%    89.89%    -0.03%
==========================================
  Files          192       193        +1
  Lines        23809     24022      +213
  Branches      8218      8310       +92
==========================================
+ Hits         21409     21594      +185
- Misses        2400      2428       +28
- Partials      1339      1357       +18

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