OST-1136: add autopilot run cancellation

[BeliyDym]

Summary

• add run-scoped autopilot cancellation API at POST /api/autopilot-runs/{runId}/cancel
• expose CLI command: multica autopilot runs cancel
• add cancelled autopilot_run terminal status, tests, CLI docs, and built-in skill source map updates

Verification

• /tmp/go1.26.1/go/bin/go test ./cmd/multica
• /tmp/go1.26.1/go/bin/go test ./internal/handler -run 'TestCancelAutopilotRun'
• /tmp/go1.26.1/go/bin/go test ./internal/service -run TestAutopilotsSkillCoversDispatchAndSideEffects
• git diff --check
• /tmp/go1.26.1/go/bin/go run ./cmd/multica autopilot runs cancel --help

[vercel]

@BeliyDym is attempting to deploy a commit to the IndexLabs Team on Vercel.

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