[P0] Implement bounded verify→repair self-healing loop

[pro-utkarshM]

Problem

The proposal's core innovation is an iterative verification loop that repairs failing tests until pass. Reality: core/generator.py:285-322 runs tests once, records tc.diagnosis, and never applies a fix or re-runs. 'Self-healing' is currently a no-op during generation.

Tasks

• Add bounded loop in generator phase 3 (e.g. max_repair_iters, default 3).
• On TEST_WRONG diagnosis: apply diagnosis.suggested_fix, regenerate test file, re-run.
• On CODE_BUG: flag, stop repairing (do not mutate test to force pass).
• On INTENT_WRONG: surface for intent revision (interactive) or skip (auto).
• Track iteration count + final status in VerificationResult.

Acceptance

A deliberately-wrong generated test gets diagnosed, auto-fixed, and passes on re-run within max iters; loop terminates and is unit-tested.