docs(inference-gateway): recover EPP developer build docs

[sttts]

Summary

• Add Go EPP developer build, test, image, and cleanup notes under deploy/inference-gateway/epp/DEVEL.md.
• Add Rust ext_proc EPP developer build, test, image, runtime, and cleanup notes under deploy/inference-gateway/ext-proc/DEVEL.md.
• Keep build-your-own-image details out of the user-facing GAIE guide and close the documentation gap in the component directories.

Validation

• Pre-commit hooks from signed commit.
• rg style check for trailing whitespace, TODO/FIXME, docs.nvidia.com self-links, and banned filler terms.

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Summary by CodeRabbit

• Documentation
  • Added developer guides for two inference gateway components.
  • Documented setup prerequisites, local build and test steps, image build/load/push workflows, and cleanup commands.
  • Included guidance for host-native development, multi-arch builds, and runtime notes such as ports and TLS behavior.

[copy-pr-bot]

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[github-actions]

🌿 Fern Docs Preview: https://nvidia-preview-0dd14102-4892-4ec6-bfe7-515827625d56.docs.buildwithfern.com/dynamo/dev

[sttts]

/ok to test 64422f9

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: b8a6a8c5-dbc9-4bfc-91ec-d095e4bba3e5

📥 Commits

Reviewing files that changed from the base of the PR and between 91b6259 and 64422f9.

📒 Files selected for processing (2)

• deploy/inference-gateway/epp/DEVEL.md
• deploy/inference-gateway/ext-proc/DEVEL.md

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Walkthrough

Adds developer documentation for the Dynamo EPP and Rust ext_proc inference-gateway plugins, covering build, image, runtime, test, and cleanup workflows.

Changes

Dynamo EPP developer guide

Layer / File(s)	Summary
EPP development guide deploy/inference-gateway/epp/DEVEL.md	Documents prerequisites, image build/load/push workflows, host-native build steps, dev checks, and cleaning behavior for the Dynamo Endpoint Picker Plugin.

Rust ext_proc developer guide

Layer / File(s)	Summary
ext_proc development guide deploy/inference-gateway/ext-proc/DEVEL.md	Documents prerequisites, host-native build and test commands, image build/push workflows, runtime notes, and cleanup steps for the Rust ext_proc plugin.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description misses the required template sections for Details, reviewer start, and Related Issues.	Rewrite the description using the template sections and add the required Related Issues entry or explicit no-issue confirmation.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: restoring EPP developer build documentation under inference-gateway.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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