docs: add epoch 3.3 activation to config examples

[unclekaldoteth]

Fixes #1742

Summary

• Update testnet configuration examples to include epoch 3.3.
• Add epoch 3.3 activation height 108_800 immediately after epoch 3.2 in reference config snippets.
• Keep docs aligned with stacks-core epoch 3.3 activation changes.

Changes

• docs/reference/README.md
  • Added:
  • epoch_name = "3.3"
  • start_height = 108_800
• docs/reference/node-operations/signer-configuration.md
  • Added epoch 3.3 (108_800) in the testnet signer+node sample config.
• docs/reference/nakamoto-upgrade/setting-up-a-primary-post-nakamoto-testnet-node.md
  • Added epoch 3.3 (108_800) in both testnet node config examples.

Testing

npx --yes markdownlint-cli --disable MD001 MD013 MD022 MD024 MD031 MD034 MD036 MD040 -- docs/reference/README.md docs/reference/node-operations/signer-configuration.md docs/reference/nakamoto-upgrade/setting-up-a-primary-post-nakamoto-testnet-node.md
echo "exit_code=$?"
# exit_code=0

Checklist

• Required documentation updates included
• Changes are scoped to docs only
• Test evidence included

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