fix: restore fuzzy and Unicode tape search

[yunyv]

Summary

Restore fuzzy and Unicode matching in FileTapeStore:

• Clear the parent query's exact-substring filter before applying the existing fuzzy matcher. Keep the structural filters, and apply the requested limit after fuzzy matching and deduplication.
• Preserve Unicode when serializing payloads for matching so Chinese, accented text, and emoji can match their visible text.
• Add 15 regression cases covering persisted payloads, exact/case-insensitive/fuzzy/Unicode matches, rejected queries, anchors, dates, kinds, newest-first deduplication, limits, query immutability, and unchanged unqueried ordering.

This addresses the separate tape-search follow-up described in #361. The current parent filter rejects deploymnt before the fuzzy matcher can compare it with deployment; Unicode is additionally escaped in the text passed to that matcher.

Validation

• New regression tests on the unchanged source: 9 failed, 6 passed.
• New regression tests with this fix: 15 passed.
• Full suite, including doctests: 628 passed, 1 skipped (PowerShell unavailable).
• make check: passed all hooks and mypy (57 source files).

The full-suite run used a writable temporary HOME and OTEL_TRACES_SAMPLER=always_on because the execution environment otherwise has a read-only home and an inherited tracing sampler. No application code was changed for those environment constraints.