fix(shell): auto-repair DNS resolution at container startup

[konard]

Summary

Docker's internal DNS resolver (127.0.0.11) intermittently loses its upstream nameservers, causing domain resolution to fail inside containers. This breaks git clone, package installs, and any network operations.

Fixes #168

Changes

• DNS repair at startup (dns-repair.ts → entrypoint template): probes github.com via getent hosts at container boot; if resolution fails, appends fallback nameservers (8.8.8.8, 8.8.4.4, 1.1.1.1) to /etc/resolv.conf
• Explicit DNS in docker-compose (docker-compose.ts template): adds dns: section to both main service and browser sidecar, ensuring containers always have working external DNS regardless of Docker daemon configuration
• Example files updated: root docker-compose.yml and entrypoint.sh updated to match

Root cause

When Docker creates a container network, it configures 127.0.0.11 as the DNS resolver in /etc/resolv.conf. This internal resolver forwards queries to the host's DNS. However, on some hosts (especially when the Docker daemon is restarted or the network stack changes), the internal resolver loses its upstream configuration, leaving containers unable to resolve any external domains.

Математические гарантии

Инварианты:

• ∀container: startup(container) → dns_healthy(container) ∨ dns_repaired(container)
• ∀service ∈ compose: dns(service) = [8.8.8.8, 8.8.4.4, 1.1.1.1]

Предусловия:

• Container has network access to at least one of the fallback DNS servers

Постусловия:

• /etc/resolv.conf contains at least one working nameserver
• getent hosts github.com succeeds (or warning is logged)

Сложность:

• Время: O(1) per DNS probe attempt
• Память: O(1) — appends at most 3 lines to resolv.conf

Test plan

• pnpm --filter ./packages/lib typecheck passes
• pnpm --filter ./packages/app check passes
• pnpm --filter ./packages/lib test — all 86 tests pass
• Manual: verify DNS repair works in a container with broken Docker DNS

🤖 Generated with Claude Code

[konard]

🤖 Solution Draft Log

This log file contains the complete execution trace of the AI solution draft process.

💰 Cost estimation:

• Public pricing estimate: $3.739659
• Calculated by Anthropic: $2.554058 USD
• Difference: $-1.185602 (-31.70%)

🤖 Models used:

• Tool: Claude
• Requested: opus
• Main model: Claude Opus 4.6 (ID: claude-opus-4-6, Anthropic, cutoff: 2025-05)
  📎 Log file uploaded as Gist (1351KB)
  🔗 View complete solution draft log

---

Now working session is ended, feel free to review and add any feedback on the solution draft.

[konard]

✅ Ready to merge

This pull request is now ready to be merged:

• All CI checks have passed
• No merge conflicts
• No pending changes

---

Monitored by hive-mind with --auto-restart-until-mergeable flag

[skulidropek]

покрой код тестами