Add Continuous Receiver Gathers template and grid override

[BrianMichell]

Proposes implementation for CRG template and custom override to support epoch-based sensor chunking

EDIT: This PR has been reset to a draft so we can implement better defined templates and re-evaluate the requirements for multi-receiver gathers.

[codecov]

Codecov Report

❌ Patch coverage is 98.84615% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.34%. Comparing base (c3ba558) to head (c772040).
⚠️ Report is 250 commits behind head on main.

Files with missing lines	Patch %	Lines
src/mdio/ingestion/segy/index_strategies.py	94.91%	1 Missing and 2 partials ⚠️
tests/integration/conftest.py	96.59%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #851      +/-   ##
==========================================
+ Coverage   85.30%   93.34%   +8.03%     
==========================================
  Files          46      148     +102     
  Lines        2219     8785    +6566     
  Branches      306      490     +184     
==========================================
+ Hits         1893     8200    +6307     
- Misses        281      508     +227     
- Partials       45       77      +32     

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[andgineer]

@BrianMichell
This branch is cut from main before #852, so anything pinning refs/pull/851/head resolves zarr unbounded, picks up 3.3.0, and dies at import:

pydantic.errors.PydanticSchemaGenerationError: Unable to generate pydantic-core schema
for <class 'zarr.codecs.blosc.BloscCname'>

Could you merge main into the branch? It needs the rebase before it merges anyway..