Fix input queue deadlock after session rebound

[Pigbibi]

Summary

• scope unresolved input confirmation locks to the authoritative bound window after a topic rebind
• retire superseded confirmations after a read-only transcript check, without replaying old text
• keep route-wide serialization while a rebind is unconfirmed or ambiguous
• add regression coverage for the production deadlock and durable target filtering

Root cause

A submitted_unconfirmed record tied to a hibernated tmux window continued locking the entire Telegram topic after the topic resumed in a new window. Later messages entered the Bot FIFO but its drainer could never start, so users saw Queued until the agent is ready indefinitely instead of native steer/queue handling.

Verification

• rtk ruff check src/ tests/
• rtk ruff format --check src/ tests/
• rtk pyright src/telegram_agent_bot/
• rtk pytest (816 passed)

[github-actions]

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