[guido4096]

Adding a 256th string could wrap the pool's 8-bit entry counter and invalidate previously issued IDs. Insertion and lookup were also unsynchronized across tasks, and strings longer than the 8-bit length representation were not rejected.

Limit the pool to 255 addressable entries, reject strings longer than 255 bytes, and synchronize insertion/lookup. Existing strings remain accessible when entry or byte capacity is exhausted; further new strings return ID 0.

Validation

• 172 host tests passed on this standalone branch (macOS, POSIX enabled, original pinned eBUS revision f730dce).
• Whitespace checks passed. CI and a fresh firmware build for this isolated branch are pending.
• For the standalone macOS test run, the two mock-file fixes from part 1/5 were applied as temporary, uncommitted test-only overrides. Those files are not included in this PR.

Regressions cover entry exhaustion, byte exhaustion, oversized names, preservation of existing IDs and concurrent interning without duplicate IDs.

Device check before marking ready

Verify normal command/MQTT operation under concurrent use and sustained operation. The tests establish the covered capacity and concurrency behavior; they do not establish on-device timing or measured performance improvements.

Related runtime fixes

Part 4/5 of the single-commit replacements for #430, split at the maintainer's request. Every PR targets master directly and contains only its corresponding change.

Part	Scope	PR / branch
1/5	Correct host-test mocks	#431
2/5	Bound Logs page retention	#432
3/5	Schedule diagnostics by elapsed time	#433
4/5	Protect string-pool IDs and concurrent access	#434
5/5	Buffer HTTP streams and stop after send failures	#435

Suggested merge order: the host-test mock fix first, then the other four changes independently. The five patches together reconstruct the exact tracked file tree of #430.

Source commit in #430: d8a436e.