Add bundled OKF index template

[VimCommando]

Summary

• bundle an OKF v0.2 Elasticsearch template and resolve it with --template _okf
• create or update the shared open-knowledge-format template by appending exact target index names
• support --template-name overrides for bundled templates while preserving file-backed behavior
• map official OKF metadata explicitly and map unknown strings as bounded keywords
• sync and archive the completed OpenSpec change

Verification

• cargo fmt --check
• cargo test (215 passed, 5 ignored)
• strict OpenSpec validation
• packaged crate contains assets/templates/_okf.yaml

[Copilot]

🟡 Changes recommended

Bundled template selector validation currently runs before output-type validation, which can produce misleading errors for non-Elasticsearch outputs using --template _....

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR adds first-class support for bundled (embedded) Elasticsearch composable index templates—starting with an Open Knowledge Format (OKF) v0.2 template selected via --template _okf—and updates the Elasticsearch preflight flow to create/merge a shared cluster-side template by appending exact target index names while preserving stored fields.

Changes:

• Embed and resolve bundled templates via rust-embed, including _okf with explicit OKF v0.2 mappings and a bounded keyword dynamic template for unknown strings.
• Extend template installation logic to (for bundled templates) GET the selected cluster-side template, create it if missing, or append the exact target index into index_patterns when absent.
• Add comprehensive unit/integration tests, OpenSpec specs/archives, and documentation updates (README, skill, changelog, examples).

File summaries

File	Description
tests/fixtures/okf_v0_2.ndjson	Adds representative OKF v0.2 fixture documents.
tests/bundled_template.rs	Adds end-to-end request-capture tests for bundled template behavior.
src/output/mod.rs	Adds preflight validation hook for bundled template selectors.
src/output/elasticsearch/embedded_templates.rs	Implements embedded template catalog + mapping/fixture tests.
src/output/elasticsearch.rs	Adds TemplateSource + bundled install/merge logic for templates.
src/main.rs	Adjusts startup ordering to preflight bundled templates before input construction.
src/input.rs	Adds lightweight multi-source local discovery helper used during startup.
README.md	Documents bundled template selection and OKF template semantics.
openspec/specs/okf-index-template/spec.md	Defines OKF bundled template mapping requirements.
openspec/specs/elasticsearch-index-template/spec.md	Specifies bundled selector semantics + merge behavior.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/tasks.md	Archives completed implementation task checklist.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/specs/okf-index-template/spec.md	Archives the OKF index template spec snapshot.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/specs/elasticsearch-index-template/spec.md	Archives the ES template selector/merge spec snapshot.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/proposal.md	Archives the change proposal.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/design.md	Archives the design rationale and trade-offs.
openspec/changes/archive/2026-08-27-add-bundled-okf-template/.openspec.yaml	Adds OpenSpec metadata for the archived change.
examples/steam-games/steam-games-template.yaml	Adds/renames example template to .yaml.
examples/steam-games/steam-games-pipeline.yaml	Adds/renames example pipeline to .yaml.
examples/steam-games/readme.md	Updates example command to .yaml filenames.
CHANGELOG.md	Notes the new bundled _okf template feature.
Cargo.toml	Includes embedded assets in packaging and adds rust-embed dependency.
Cargo.lock	Locks new dependency graph for rust-embed.
assets/templates/_okf.yaml	Adds the bundled OKF v0.2 composable index template asset.
.agents/skills/espipe/SKILL.md	Updates the espipe skill to describe --template _okf usage.

Review details

• Files reviewed: 21/24 changed files
• Comments generated: 1
• Review effort level: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

🔵 Needs a closer look

It introduces a new embedded-asset pipeline and modifies Elasticsearch preflight/installation behavior, warranting final human validation despite strong test coverage.

Review details

• Files reviewed: 22/25 changed files
• Comments generated: 0 new
• Review effort level: Lite