refactor: remove loader global state

[Teagan42]

What

• replace mutable loader globals with runtime configuration objects and updated helpers
• drop the private channel aliases and teach ingestion to use the shared types directly
• update loader tests and helpers to pass explicit configuration and bump the project version

Why

• keep configuration near its usage so IMDb and Qdrant helpers can be reused without global mutation

Affects

• loader runtime configuration, pipeline channels/ingestion, loader unit/integration tests

Testing

• uv run ruff check .
• uv run pytest

Documentation

• not needed

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https://chatgpt.com/codex/tasks/task_e_68e355a592b48328a7c276e8d20d3289

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
mcp_plex/loader
__init__.py	387	18	95%	84–91, 165, 255–260, 621, 736–738, 740, 826–845, 1198
mcp_plex/loader/pipeline
__init__.py	15	7	53%	57–62, 68
channels.py	62	2	97%	19–20
enrichment.py	430	60	86%	248, 253, 284, 286, 293, 297, 376, 397, 417, 425–427, 434–437, 440–442, 450, 507, 563, 586, 590, 592, 618, 636, 648, 677, 683, 686–694, 720, 723–725, 742–744, 764–767, 771, 785–791, 813, 815, 818–820
ingestion.py	81	8	90%	66, 97–107, 128, 156, 178
orchestrator.py	85	5	94%	48, 112, 141, 164–165
persistence.py	124	9	93%	112, 154–155, 165, 170, 174–176, 214
mcp_plex/server
__init__.py	614	29	95%	43–44, 119–120, 148, 252, 256, 277–280, 297, 362, 365, 402, 420–421, 458, 1109, 1131–1137, 1173, 1191, 1196, 1214, 1338, 1375
__main__.py	4	4	0%	3–8
config.py	48	7	85%	50, 52–55, 65, 76
TOTAL	2052	149	93%

Tests	Skipped	Failures	Errors	Time
120	0 💤	0 ❌	0 🔥	47.807s ⏱️