Two-thumb: tapping 'i' doesn't autocorrect to 'I'

[SHAWNERZZ]

Summary

Tapping a single-letter word like i then space commits the literal i instead of autocorrecting to I, when typing in two-thumb mode.

Repro

1. Two-thumb spacing mode on.
2. Tap i, then space.
3. Result: i (expected I).

Root cause (traced, medium confidence)

The space-commit path does call autocorrect (handleSeparatorEvent → commitCurrentAutoCorrection), but that only substitutes when mWordComposer.getAutoCorrectionOrNull() is non-null. In the log the strip was words=[i|I|I'm|it|in] — i is the typed word kept as valid, I only a lower-ranked suggestion, so Suggest set no autocorrection and the literal i committed.

Most likely the C4 "learned-typo" feedback loop: each lowercase i commit reinforces i in the user-history dictionary, making Suggest treat it as a real word and suppress the i→I correction further. This is a dictionary/Suggest data issue, not the casing fix (#6) — the i tap never routes through the gesture-commit path that #6 touched.

Needs one disambiguation test

• If i→I also fails with two-thumb OFF (plain typing) → learned-lowercase-i (C4 territory: blocklist / graduated trust) or an autocorrect-setting issue.
• If it works with two-thumb OFF but fails ON → the two-thumb commit path is suppressing the autocorrection; fix is in InputLogic's combining/fragment commit.

Options (pending the test)

• Confirm with the test above, then target the correct layer.
• If learned-i: clear/relearn (the merged C4 blocklist + graduated-trust should help); ensure i isn't promoted to trusted.
• If two-thumb path: ensure a single-letter tapped word committed via the two-thumb path runs the same autocorrect as a plain tap+space.