feat: waiting-for-input detection and resolved state for tmux sessions

[snibbor2]

Summary

Adds automatic detection when a monitored tmux session is blocked waiting for user input — prompts, password fields, `[y/n]` confirmations, Claude Code tool-approval dialogs, etc. — and delivers an alert to the configured Discord channel. When input is provided and the session resumes, a resolved notification is sent.

• Detects 30+ interactive prompt patterns across the last 3 non-empty pane lines
• Fires `tmux.waiting_for_input` event on transition from active → blocked
• Fires resolved notification on transition from blocked → active
• Integrates with dashboard pinning (`pin_alerts = true`) to edit the alert in-place rather than flooding the channel

Config example

[[monitors.tmux.sessions]]
session = "my-agent"
detect_waiting = true
channel = "1234567890"

Detected patterns include

• `[y/n]`, `(y/n)`, `[yes/no]` confirmation prompts
• `password:`, `passphrase:`, `enter password`
• `press enter`, `press any key`
• Claude Code / OMC tool-approval: `allow, deny`, `allow this action`, `always allow`, `approve or deny`
• Interactive menu selectors (`❯` prefix or `? ` suffix)
• SSH/sudo credential prompts

Three regression tests added for this case.

Test plan

• `cargo test` — 340 tests passing (branch total)
• Live integration tested: `read -p "Confirm? [y/n]: "` triggered alert within one poll cycle; typing `y` produced `✅ session — Input received, continuing...` edited into the alert slot within 10 seconds
• `sudo` password prompt detected and resolved correctly
• No false-positives during rapid continuous output