fix(input): cap console history growth (B3)

[Vadim1987]

Console history grows for the whole session: History:remember only ever appends, and nothing evicts, so on a long session every entered command accumulates in memory (each entry is a string[] of lines).
The fix caps history at 100 entries: after an append, _trim evicts from the front while over the limit. Since the backing store is a plain array, eviction shifts indices, so _trim also shifts self.index when arrow-key navigation is active — the position keeps pointing at the same entry — and resets it if the navigated-to entry itself was evicted.
The limit is a named constant; 100 entries comfortably covers a session on the device while keeping the worst case bounded.

[dsent]

@aldum What is our policy on tests? Do we add extensive automated tests like there are in the last few Vadim's PRs or not? I remember @nagydani being sceptical of extensive automated testing.

[aldum]

My opinion is, short of a compiler, static checks and tests are the only thing standing between us and pervasive bugs. And we still get bugs.

[dsent]

@aldum do you approve this PR, then?

[aldum]

@dsent Not as such, no. I'd like to see a config option, at least in-code.
0 should mean unlimited history, and I think the default should be a tad higher, it's just plaintext after all

[aldum]

Great stuff!

[Vadim1987]

Done: the limit is a constructor parameter fed from the config ("input_history" in baseconf, in-code as suggested), 0 means unlimited, default raised to 1000.