Bound LCM protocol payloads

[mjc]

Bounds LCM protocol inputs before storing or forwarding them.

Changes

• Copy poll names within the fixed name buffer and always terminate them.
• Clamp the three brightness percentages to the schema-defined 0–100 range.
• Clear one-shot payload state for every enabled light-control request, including malformed short requests.
• Cap forwarded payloads at the fixed 64-byte storage capacity.
• Remove the unreachable disabled-module branch from the enabled-only handler.

Behavior

Valid LCM traffic is unchanged. Oversized names and payloads stay within their fixed buffers, and a rejected short light-control request cannot leave an older payload queued for the next poll response.

I was able to cause a crash on the existing code with enough BTLE packets.

[Copilot]

Pull request overview

This PR hardens the LCM (Light Control Module) protocol handling by bounding/normalizing incoming fields before storing them and before forwarding them back out, preventing out-of-bounds copies and invalid/stale payload behavior.

Changes:

• Bound and null-terminate copied LCM name strings to avoid overruns.
• Clamp brightness bytes to the protocol’s 0–100 range and cap stored/forwarded payload length to fixed capacity.
• Reset per-request payload state and simplify the enabled-only light-control handler.

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[lukash]

I think the changes in the two commits in this PR should ideally be split into 3 commits:

• the simplification of the name copying code
• limiting the brightnesses to max 100
• handling the payload size overflow / clearing on short request