fix(quickstart): align Go and Python env files with upstream repos

[sunshinexcode]

Summary

Align Python and Go quickstart env detection/writes with the current upstream repository layouts. Python and Go quickstarts now write server/.env.local with AGORA_APP_ID / AGORA_APP_CERTIFICATE, and Go quickstarts are no longer misdetected as Python.

This also updates README and agora skills wording to describe the actual Go ConvoAI quickstart instead of the stale token-service recipe.

Type of change

• Bug fix (non-breaking)
• New feature (non-breaking, additive)
• Behavior change to an existing command (potentially user-visible)
• Breaking change (CLI flag, exit code, JSON shape, or error.code rename/removal)
• Documentation only
• CI / packaging / tooling
• Refactor (no behavior change)

Public-contract impact

• No public-contract impact.
• Adds or changes a JSON envelope shape — described below.
• Adds a new error.code — added to docs/error-codes.md.
• Renames or removes an error.code — flagged as breaking, included in CHANGELOG.
• Changes an exit code for an existing command — flagged as breaking.
• Adds or changes a CLI flag — documented in help text and (if user-facing) docs/automation.md.

No JSON envelope shape, exit code, error.code, or CLI flag changes.

The user-visible behavior change is limited to where Python/Go quickstart env files are written and which env keys are injected.

Test plan

• go test ./... passes locally.
• make lint passes locally (gofmt, golangci-lint, error-code coverage audit).
• New behavior is covered by JSON-mode integration tests in internal/cli/.
• Edge cases are covered by unit tests in internal/cli/app_test.go (where applicable).

Additional local checks run:

go vet ./...
go run ./cmd/gendocs -check
go build -o .tmp/agora .
git diff --check

Manually verified:

go run . quickstart list --details --json
go run . skills show create-go-voice-agent --json

Documentation

• CHANGELOG.md updated under ## Unreleased (Fixed).
• docs/automation.md updated for quickstart env behavior.
• docs/error-codes.md N/A: no new error.code.
• README.md updated for quickstart wording.
• AGENTS.md N/A: no engineering or release process change.

Security checklist

• No credentials, App Certificates, tokens, or PII added to fixtures, logs, or test output.
• No new outbound network call without timeout / context cancellation.
• No new file written under user $HOME without 0o600 perms when it can contain credentials.
• No new unsafe import.

Additional notes

The local git fixture setup remains test-scoped only. Production quickstart clone behavior does not set GIT_ALLOW_PROTOCOL=file and still uses shallow clones.