feat(dashboard): add sequential task session control

[wilburx813]

Summary

• turn the Dashboard into one long-lived Claude Code control Session. [1] [2]
• add the strict local /rpent-task <suite> <task> <seed> command and sequential fresh TaskRuns. [1] [2]
• reuse Session-owned VLA/SAM3 services while recreating the env, toolkit, planner conversation, and artifact directory for every TaskRun. [1] [2]
• support last-write-wins task replacement and suite-name suggestions in the composer. [1] [2]
• stop active Dashboard tools at their next safe boundary before interrupting the planner. [1] [2]
• derive Dashboard-only action clips from the event sink and preserve concurrent LIBERO runtime startup. [1] [2]

Usage

The launcher now starts a Session rather than selecting a task. Once shared services are ready, the composer accepts /rpent-task; completed or failed TaskRuns return to command-only mode. Each accepted command gets a fresh env, toolkit, planner conversation, counters, and artifacts.

Pressing Esc requests Toolkit cancellation first, waits for the next environment-defined safe boundary, and then interrupts Claude. Task replacement keeps its existing natural-drain behavior.

Follow-up

• Update doc docs: update Dashboard session documentation #70
• support different planner

[wilburx813]

[qurakchin]

need to update docs

[wilburx813]

need to update docs

updated in a separate pr #70