fix(mcp-server): drop undefined cron, pass tier run notes, 1800s timeout, current examples

[aaronjmars]

Four small drifts between the local MCP server (apps/mcp-server) and the scheduled run path.

What changed

1. No more "(cron: undefined)" in tool descriptions. catalog/skills.json stopped carrying schedules (see bin/generate-skills-json), so every tool description ended in "(cron: undefined)". The server now reads each skill's schedule: from its line in aeon.yml, using the same single-line lookup it already uses for the per-skill harness: (now one shared helper). Descriptions show "(cron: )", "(on-demand)" for workflow_dispatch, "(reactive)" for reactive, and no suffix if a skill has no aeon.yml entry. Skill.schedule is now optional.
2. Tier run notes reach the harness. The workflow passes --append-system-prompt "$(scripts/skill_mode.sh run-notes <mode>)" to run-harness; the MCP path did not. It now calls the same run-notes command for the resolved mode and passes it the same way (only when non-empty, like the workflow).
3. Timeout matches the workflow. The server used 600s; the workflow passes --timeout 1800 to run-harness. Both the run-harness flag and the Node kill timer now use one 1800s constant. The README line that claimed the old value matched Actions is corrected.
4. Real example tools. bin/add-mcp suggested aeon-hn-digest and aeon-deep-research, which no longer exist. They are now aeon-digest and aeon-article (both in catalog/skills.json). Also fixed the stale index.ts header example and the wrong script path in docs/examples/mcp/test_connection.py.

How it was verified

• npm run build and npm run typecheck in apps/mcp-server pass.
• Spoke MCP over stdio (initialize + tools/list): 85 tools, equal to the 85 catalog entries, none containing "undefined". Suffixes: 49 cron, 35 on-demand, 1 reactive.
• No-cost run test with a fake claude on PATH that dumps its argv: called aeon-heartbeat (write) and aeon-competitor-monitor (read-only) through tools/call. Both returned the fake result, and the --append-system-prompt value the fake received was byte-identical to scripts/skill_mode.sh run-notes <mode> for each tier.
• shellcheck bin/add-mcp is clean and scripts/lint-shell.sh passes; the add-mcp banner still lines up.