Align CI with centralized E2E workflow

[casey-brooks]

Summary

• Aligns E2E workflow with centralized architecture: provision via agynio/bootstrap/.github/actions/provision@main, build agn from source through devspace dev, then run agynio/e2e/.github/actions/run-tests@main.
• Removes pinned shared agynio action refs and ref overrides.
• Removes the repo-local E2E runner deployment/pipeline from devspace.yaml; E2E execution now stays centralized in agynio/e2e.
• Adds top-level read-only workflow permissions and verifies PR workflows do not build/publish images/charts or override bootstrap cluster environment.

Closes #62

Test & Lint Summary

• actionlint .github/workflows/ci.yml .github/workflows/e2e.yml .github/workflows/release.yml — passed with no errors.
• yamllint -d '{extends: default, rules: {line-length: disable, document-start: disable, truthy: disable}}' .github/workflows/ci.yml .github/workflows/e2e.yml .github/workflows/release.yml devspace.yaml — passed with no errors.
• go vet ./... — passed with no errors.
• go test ./... — 10 packages passed, 0 failed, 0 skipped.
• go build ./cmd/agn — passed.
• go build ./... — passed.

Note

• devspace dev was syntax-checked via devspace print --debug. Full local execution requires a valid kubeconfig; without a cluster, DevSpace exits before running the pipeline.

[casey-brooks]

Test & Lint Summary

• actionlint .github/workflows/ci.yml .github/workflows/e2e.yml .github/workflows/release.yml — passed with no errors.
• yamllint -d '{extends: default, rules: {line-length: disable, document-start: disable, truthy: disable}}' .github/workflows/ci.yml .github/workflows/e2e.yml .github/workflows/release.yml devspace.yaml — passed with no errors.
• go vet ./... — passed with no errors.
• go test ./... — 10 packages passed, 0 failed, 0 skipped.
• go build ./cmd/agn — passed.
• go build ./... — passed.

Note: devspace dev was syntax-checked via devspace print --debug. Full local execution requires a valid kubeconfig; without a cluster, DevSpace exits before running the pipeline.

[casey-brooks]

Fix validation

Local tests

• go test ./... / CGO_ENABLED=0 go test ./...: passed locally for the changed Go packages/repos; 0 failed.
• CGO_ENABLED=0 go test ./internal/mcp -run TestShellToolTruncation -count=100 -v: 100 passed, 0 failed, 0 skipped.

Lint/config validation

• actionlint: passed with no errors.
• yamllint -d '{extends: default, rules: {line-length: disable, document-start: disable, truthy: disable}}': passed with no errors.
• devspace print --debug: passed for DevSpace-edited repos.
• git diff --check: passed with no whitespace errors.

Pushed the CI/E2E fix commit and GitHub Actions reran from the new head commit.