[FR] Update Reference Material to Include New Config Options

[eric-forte-elastic]

Summary

Updates the root-level DaC documentation to match elastic/detection-rules#5869: fine-grained optional validation bypasses in _config.yaml, new DR_BYPASS_ESQL_* environment variables, and clearer wording around local ES|QL checks versus remote stack validation.

Why

PR #5869 adds:

• bypass_optional_elastic_validation: true — still enables all optional bypasses at config load.
• Per-check flags (when the bulk flag is false or omitted): bypass_note_validation_and_parse, bypass_bbr_lookback_validation, bypass_tags_validation, bypass_timeline_template_validation, bypass_esql_keep_validation, bypass_esql_metadata_validation — each sets the matching DR_BYPASS_* at load time.
• Env vars for narrow ES|QL bypasses: DR_BYPASS_ESQL_KEEP_VALIDATION, DR_BYPASS_ESQL_METADATA_VALIDATION.

The reference previously implied ES|QL was not validated locally at all; the repo does run some local semantic checks (metadata / keep expectations) while full syntax and semantics still require a cluster.

Files changed

File	Change
docs/dac_quick_start_guide.md	ES
docs/internals_of_the_detection_rules_repo.md	Note after custom _config.yaml example on fine-grained bypasses and bulk-flag precedence.
docs/etoe_reference_example.md	Pointer to quick start §6 and upstream _config.yaml for fine-grained options.

References

• detection-rules PR #5869
• Upstream example config: detection_rules/etc/_config.yaml

[Mikaayenson]

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