[PHP] Show files-pull checkpoint lifecycle in tests

[adamziel]

Rewrites the files-pull diff checkpoint tests so the full lifecycle can be read from each test body.

Each test now shows the retained remote index, the next remote index, the interruption point, the resumed operation, and the files or paths observed afterward. Scenario setup and result reads no longer hide behind one-purpose helpers. The remaining helpers only create the client, encode or decode JSONL records, call the private diff method, load saved state, and remove temporary files.

The suite is renamed to FilesPullDiffCheckpointTest because its main subject is the checkpoint shared by the index diff, fetch list, and pull WAL.

Testing

cd tests
../vendor/bin/phpunit Import/FilesPullDiffCheckpointTest.php Import/PullIndexWalTest.php Import/FileIndexDiffProcessorTest.php

[github-actions]

Pull pipeline performance — large-directory

Site: large-directory · 2,000+ plus targeted file-transfer scenarios files · 10,000 posts · 25,000 postmeta · PHP 8.5.9

Stage	PR	trunk	Δ	Status	Details
playground-sqlite-db-pull	10.09 s	9.67 s	⚪ +424 ms (+4.4%)	✓	condition=db-pull in PHP.wasm runtime=php.wasm 8.3 wp_mysql_parser=enabled mode=lexer native_lexer=verified native_token_stream=WP_MySQL_Native_Token_Stream native_token_count=18 native_parser=selected trunk: condition=db-pull in PHP.wasm runtime=php.wasm 8.3 wp_mysql_parser=enabled mode=lexer native_lexer=verified native_token_stream=WP_MySQL_Native_Token_Stream native_token_count=18 native_parser=selected
playground-sqlite-db-apply	3.69 s	3.93 s	⚪ -235 ms (-6.0%)	✓	condition=db-apply to SQLite in PHP.wasm runtime=php.wasm 8.3 wp_mysql_parser=enabled mode=parser native_lexer=verified native_token_stream=WP_MySQL_Native_Token_Stream native_token_count=18 native_parser=verified native_ast=WP_MySQL_Native_Parser_Node sqlite_driver_parser=verified trunk: condition=db-apply to SQLite in PHP.wasm runtime=php.wasm 8.3 wp_mysql_parser=enabled mode=parser native_lexer=verified native_token_stream=WP_MySQL_Native_Token_Stream native_token_count=18 native_parser=verified native_ast=WP_MySQL_Native_Parser_Node sqlite_driver_parser=verified
Total	13.78 s	13.59 s	⚪ +189 ms (+1.4%)

_{Numbers carry runner noise; treat single-run deltas as directional, not authoritative.}

_{📈 Trunk performance history — commit-by-commit timeline.}