Improve save protocol and SQLite pragmas

[GlassOfWhiskey]

Replace persistence_lock: Lock with _saving: Event in PersistableEntity so concurrent callers wait on a shared event rather than serialize through a mutex. Each save method also gains an early-return guard and moves follow-on writes (ports, steps, dependencies) inside the guarded block to avoid redundant work on re-entry. Remove LocalTarget._get_deployment_config() class-level singleton as it is no longer needed.

Replace PRAGMA wal_autocheckpoint with PRAGMA temp_store = MEMORY, PRAGMA foreign_keys = ON, and PRAGMA mmap_size in the SQLite connection setup. Expose mmap_size as a configurable option (default 256 MiB) in the schema and SqliteDatabase constructor.

[codecov]

Codecov Report

❌ Patch coverage is 80.64516% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.20%. Comparing base (7a61258) to head (70c8251).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
streamflow/core/workflow.py	64.28%	6 Missing and 4 partials ⚠️
streamflow/core/deployment.py	90.90%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1036      +/-   ##
==========================================
- Coverage   74.25%   74.20%   -0.06%     
==========================================
  Files          90       90              
  Lines       12461    12478      +17     
  Branches     2182     2186       +4     
==========================================
+ Hits         9253     9259       +6     
- Misses       2689     2696       +7     
- Partials      519      523       +4     

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