* Memory/QMD: symlink default model cache into custom XDG_CACHE_HOME
QmdMemoryManager overrides XDG_CACHE_HOME to isolate the qmd index
per-agent, but this also moves where qmd looks for its ML models
(~2.1GB). Since models are installed at the default location
(~/.cache/qmd/models/), every qmd invocation would attempt to
re-download them from HuggingFace and time out.
Fix: on initialization, symlink ~/.cache/qmd/models/ into the custom
XDG_CACHE_HOME path so the index stays isolated per-agent while the
shared models are reused. The symlink is only created when the default
models directory exists and the target path does not already exist.
Includes tests for the three key scenarios: symlink creation, existing
directory preservation, and graceful skip when no default models exist.
* Memory/QMD: skip model symlink warning on ENOENT
* test: stabilize warning-filter visibility assertion (#12114) (thanks @tyler6204)
* fix: add changelog entry for QMD cache reuse (#12114) (thanks @tyler6204)
* fix: handle plain context-overflow strings in compaction detection (#12114) (thanks @tyler6204)
* Tests: harden flake hotspots and consolidate provider-auth suites
* Tests: restore env vars by deleting missing snapshot values
* Tests: use real newline in memory summary filter case
* Tests(memory): use fake timers for qmd timeout coverage
* Changelog: add tests hardening entry for #11598
