test: add crash recovery coverage and nightly storage stability checks

[egolearner]

Summary

Add recovery coverage that checks data remains queryable and writable after crashes and storage faults, including later flush, optimize, and reopen operations. The branch includes the merged FTS recovery fix #759.

• Add 18 deterministic process-crash cases across plain and dual-field FTS schemas: writes, flush, sealing, optimize, rollover, mutations, repeated recovery, and deletion of all rows.
• Share expected-state verification between checkpoint and storage workers. Check full fields, deleted keys, historical generations, exact L2 distances, small top-k ordering, and field-specific FTS terms with different frequencies and lengths. Check analytical BM25 scores for the pristine single-segment corpus; mutated corpora can retain deleted physical rows in scoring statistics.
• Verify each recovery-time mutation immediately and retain an update to a recovered document across flush/optimize/reopen.
• Prepare multiple small segments with cross-segment updates/deletions/upserts. Before optimize fault injection, finish sealing and flush; require the manifest to show multiple input segments replaced by one new segment on success.
• Add nightly block/inode exhaustion, one-shot/persistent EIO at initial and delayed writes, manifest writes, and compaction forward/vector/FTS files, plus sampled block-write replay. Require evidence of fault hits and successful writes before delayed injection; preserve logs, JUnit, seeds, and failed images.
• Generate the nightly recovery suite list from CMake registration, so new suites enter the build and runner automatically. New index types and storage paths still require explicit fault workloads.

Validation

On macOS ARM64:

• All 26 recovery tests passed through the generated suite list (18 checkpoint, 7 write, 1 optimize).
• Six plain/FTS storage-worker operation/recovery checks passed. The tightened optimize boundary was additionally rerun for both schemas, confirming three input segments and successful compaction.
• All 10 portable harness tests passed.
• Clang-tidy, Ruff, actionlint, and whitespace checks passed.

Linux validation uses the default GitHub Actions Ubuntu runner in the fork: https://github.com/egolearner/zvec/actions/runs/35495029003. This run is pending; no full Linux fault-injection pass is claimed yet. The fork-only validation commit copies this workflow to an already registered workflow path, without changing either repository's main branch. The PR does not add a pull_request trigger.

The workflow runs daily at 01:30 Asia/Shanghai after merging into the default branch and supports manual dispatch. Storage faults require sudo and loop mounts; block replay additionally requires dm_log_writes. Missing prerequisites and test failures are reported normally, without skips or expected-failure suppression. Block replay samples persistence states, not physical power cycling. No production storage behavior changes.