Burn down quarantined test suites (Character_Chat_NEW, TTS_NEW, Embeddings)

[rmusser01]

Context

PR #2579 replaced the norecursedirs hiding of three test suites with a visible quarantine (tests/_plugins/quarantine.py): tests are collected and skipped-with-reason by default, opt-in via RUN_QUARANTINED=1. The 6 ci.yml jobs whose gating shards run curated subsets of these suites set RUN_QUARANTINED: "1", so CI behavior is unchanged.

Local full-suite measurements (2026-07-02, 60s per-test timeout — includes environment-specific failures; CI's curated subsets stay green):

Suite	Failed	Passed	Skipped/xfail
tests/Character_Chat_NEW	68	408	4
tests/TTS_NEW	325	309	2 xfail
tests/Embeddings	192	230	17

Exit criteria (per suite)

1. RUN_QUARANTINED=1 pytest tldw_Server_API/tests/<suite> green in a CI-like environment (start from the ci.yml shard lists — they are the known-green inventory).
2. Remove the suite's quarantine hook from its conftest.
3. When all three hooks are gone, delete tests/_plugins/quarantine.py and audits/2026-07-02-quarantined-suites.md.

See audits/2026-07-02-quarantined-suites.md for the burn-down tracker and reproduce commands.

[rmusser01]

Completed by PR #2583, merged to dev (51372f5): all three suites re-ran green and the quarantine mechanism is fully dissolved (~1,540 tests back in default collection). The one genuine cross-test bug found (stale app-lifecycle drain state via reload_app_main) is fixed suite-locally; the underlying reload leak remains tracked in #2585.