tests: reorganize e2e_*.py into tests/e2e/ package + add missing fault-injection cases

[alokwhitewolf]

tests/e2e*.py is messy. Three top-level files, each with their own near-duplicate _run / _evo / _shutdown_dashboard / _build_repo helpers. Adding categories makes it worse.

Reorg into tests/e2e/:

• helpers.py -- shared subprocess + repo-builder helpers
• lifecycle.py, pool.py, lineage.py -- contents of the current e2e.py, e2e_pool.py, e2e_lineage.py
• dispatch_live.py -- the live dispatch tests already in e2e.py
• fault_injection.py -- new
• tests/run_e2e.py -- single runner; gates per-module on EVO_LIVE_TEST_CLAUDE

While reorganizing, add the cases the current suite doesn't cover:

• pool_state.json corruption: hand-corrupt the file, verify the recovery error fires (fault_injection.py)
• crash mid-fork with stranded lease: kill the dispatched subprocess between _mark_committed and release_lease, verify next evo new reconciles (fault_injection.py)
• concurrent evo dispatch run against the per-parent warming lock: N parallel calls with the same parent, verify exactly one explorer record gets written (dispatch_live.py, live, gated)
• deep lineage chain + compaction: chain 5+ experiments, check whether the LINEAGE re-read hint fires when the protocol gets summarized -- needed to decide Compact Instructions for lineage forking #27 (lineage.py, live, gated, ~$2-3)