[codex] Add MC0 live event streaming

[n30nex]

Summary

Adds MC0 live event streaming on top of the exact MeshCore DM routing branch.

• adds event sequence, node/message revision counters, typed EVENTS control, and a bounded MC0 event drain for node, message, and TX events
• keeps MC0 routeable addresses exact: node/thread/send/DM events use 64-hex MeshCore public-key addresses when known, with short IDs kept display-only
• adds an opt-in --mc0-tx-smoke path to the USB smoke script so COM8 validation can require a real MC0 EVT tx_status for a known client_mid
• refreshes protocol, README, inventory, and roadmap wording for the current USB-first MC0 state

Dependency

This is stacked on PR #66 (codex/mc0-exact-dm-address). Until that lands, the comparison includes the exact-DM routing foundation as part of the branch history.

Validation

Local:

• git diff --check
• python scripts\mc_companion_usb_smoke.py --help
• python -m py_compile scripts\mc_companion_usb_smoke.py scripts\serial_harness.py scripts\tdeck_smoke.py scripts\fetch_tdeck_artifact.py scripts\release_evidence.py
• pio run -e native
• .pio\build\native\program.exe --selftest
• .pio\build\native\program.exe --simtest

GitHub Actions:

• Firmware CI passed: https://github.com/ItsLimitlezz/LimitlezzOS/actions/runs/27879700387
• Artifact: tdeck-meshcore-firmware-8742c3169f58bda494a8fcf876ca195392698b32
• Manifest: env=tdeck-meshcore, meshcore_enabled=1, budget_status=pass, firmware_bytes=1583184, firmware_slot_pct=30.2, static_ram_bytes=235044

Hardware, COM8 T-Deck only:

• Flashed the downloaded MeshCore artifact with scripts\tdeck_smoke.py --port COM8 --env tdeck-meshcore --no-stub-upload --skip-build --artifact-dir ...
• esptool detected ESP32-S3 rev v0.2, MAC cc:8d:a2:0d:14:28, and verified written hashes
• Serial smoke passed id, sys, net, rf, stats, wifi, dm status, nodes, companion mc test, companion mc status
• companion mc test: MeshCore companion v0 selftest: PASS and MeshCore MC0 protocol selftest: PASS
• companion mc status: exact local MeshCore address c86a84a412fb64d5adce8114a6b3c0aec881baa0a742a76f9e85c30bc1ad5460, public=sendable, dm=sendable
• Formal MC0 USB smoke passed with --mc0-usb --mc0-tx-smoke, including MC0 EVT 2 tx_status kind=public status=queued room=public client_mid=mc0-smoke-tx
• Restored/proved radio state: Meshtastic on, MeshCore on, Balanced 50/50 split, rf smoke PASS

[n30nex]

COM8 hardware validation completed for PR #68.

Evidence:

• Firmware CI passed: https://github.com/ItsLimitlezz/LimitlezzOS/actions/runs/27879700387
• Downloaded artifact: tdeck-meshcore-firmware-8742c3169f58bda494a8fcf876ca195392698b32
• Artifact manifest: env=tdeck-meshcore, meshcore_enabled=1, budget_status=pass, firmware_bytes=1583184, firmware_slot_pct=30.2, static_ram_bytes=235044
• Flashed on COM8 only; esptool detected ESP32-S3 rev v0.2, MAC cc:8d:a2:0d:14:28, hashes verified
• Serial smoke PASS for id, sys, net, rf, stats, wifi, dm status, nodes, companion mc test, companion mc status
• Formal MC0 USB smoke PASS with --mc0-usb --mc0-tx-smoke; observed MC0 EVT 2 tx_status kind=public status=queued room=public client_mid=mc0-smoke-tx
• Restored/proved final radio state: Meshtastic on, MeshCore on, Balanced 50/50