feat(telemetry): initial implementation — OpenTelemetry traces, metrics, logs (v1.0.0)

Introduces code.nochebuena.dev/einherjar/telemetry — the observability bootstrap
starter for the Einherjar framework. Absorbs the telemetry package from micro-lib,
migrating from OpenCensus to OpenTelemetry SDK v1.42.

Bootstrap functions (not lifecycle.Component — telemetry must be initialized before
the launcher starts, and its shutdown must run after all components stop):
- New(ctx, cfg) (func(context.Context) error, error) — production mode; exports
  traces, metrics, and logs via OTLP over gRPC to the configured endpoint;
  returns a shutdown function to be deferred in main()
- NewConsole(ctx, logger, cfg) (func(context.Context) error, error) — development
  mode; writes structured telemetry to the provided logging.Logger; no network
  dependency; suitable for local development and CI

Config (EINHERJAR_OTEL_* env vars):
  ServiceName(required), ServiceVersion(unknown), Environment(development),
  OTLPEndpoint(required for New), OTLPInsecure(false)

ConsoleConfig (EINHERJAR_OTEL_* env vars):
  ServiceName(required), ServiceVersion(unknown), Environment(development)

- identifiable.go: package-level Module variable (observability.Identifiable) for version
  identification — telemetry bootstraps before the launcher; not registered as a lifecycle component

.gitea/CODEOWNERS

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+* @einherjar/CoreDevelopers @einherjar/Agents

.gitea/pull_request_template.md

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+## Summary
+
+<!-- One or two sentences: what does this PR do and why? -->
+
+---
+
+## Type of change
+
+- [ ] Bug fix — non-breaking change that resolves an issue
+- [ ] New feature — non-breaking addition of functionality
+- [ ] Breaking change — alters existing behavior or public API
+- [ ] Documentation update
+- [ ] Refactor — no functional change, no new API surface
+- [ ] Test improvement
+
+---
+
+## Description
+
+<!--
+Provide enough context for a reviewer who was not in the room:
+- What problem does this solve?
+- What approach did you choose, and why?
+- Were there alternatives you considered and rejected?
+- Any known limitations or follow-up work?
+-->
+
+---
+
+## Testing
+
+- [ ] I added or updated tests that cover my changes
+- [ ] All tests pass locally — `go test ./...`
+- [ ] No formatting issues — `gofmt -l .` produces no output
+- [ ] No vet warnings — `go vet ./...` is clean
+
+---
+
+## Checklist
+
+- [ ] At most one exported type per non-test `.go` file (CT-6)
+- [ ] No new external dependencies added without prior discussion in an issue
+- [ ] Public API changes are reflected in `CHANGELOG.md`
+- [ ] Breaking changes include a migration note in the PR description above
+
+---
+
+## Contributor License Agreement
+
+> **This PR will not be merged until the CLA comment is present.**
+
+Before a Maintainer reviews your code, you must post the following text **as a comment on this PR** — not here in the description. PR description checkboxes can be silently toggled by anyone; a comment is a timestamped, author-attributed record that cannot be quietly removed.
+
+**Copy and post this exact text as a PR comment:**
+
+---
+
+> I have read the Einherjar Contributor License Agreement (CLA.md) and I agree to all its terms.
+> I confirm this Contribution is my original work. I grant the Maintainers the rights described
+> therein, including the right to relicense, and I retain ownership of my copyright.
+> This agreement covers all future Contributions I submit to any Einherjar repository under
+> this account.
+
+---
+
+First time contributing? Read [CLA.md](../CLA.md) for the full agreement before posting the comment.
+
+If you are contributing on behalf of a company, an authorized representative of that company must post the comment.
+
+<!-- Thank you for contributing to Einherjar. For those who come after. -->