chore: init gemini customizations

[philknows]

This PR configures Gemini according to customizations to enforce our style guide. This config is experimental and is meant to give the AI code reviewer context in enforcing TigerBeetle's style guide with minor variations to suit our needs.

Examples:

• We enforce camelCase rather than SNAKE_CASE on functions and variables
• Remove unnecessary quotes and text for verbosity

[gemini-code-assist]

Note

Gemini is unable to generate a summary for this pull request due to the file types involved not being currently supported.

[github-actions]

Performance Report

✔️ no performance regression detected

Full benchmark results

Benchmark suite	Current: e1409e7	Previous: null	Ratio
get values - 1000	338.00 ns/op
get values - naive - 1000	533.00 ns/op
set values - 1000	314.00 ns/op
set values - naive - 1000	592.00 ns/op
get values - 1000000	829.00 ns/op
get values - naive - 1000000	1.9720 us/op
set values - 1000000	861.00 ns/op
set values - naive - 1000000	2.0640 us/op
JS - computeSyncCommitteeIndices - 16384 indices	317.07 ms/op
Zig - computeSyncCommitteeIndices - 16384 indices	4.0066 ms/op
JS - computeSyncCommitteeIndices - 250000 indices	302.08 ms/op
Zig - computeSyncCommitteeIndices - 250000 indices	16.891 ms/op
JS - computeSyncCommitteeIndices - 1000000 indices	315.99 ms/op
Zig - computeSyncCommitteeIndices - 1000000 indices	30.708 ms/op
JS - unshuffleList - 16384 indices	923.47 us/op
Zig - unshuffleList - 16384 indices	577.06 us/op
JS - unshuffleList - 250000 indices	13.662 ms/op
Zig - unshuffleList - 250000 indices	8.7618 ms/op
JS - unshuffleList - 1000000 indices	53.064 ms/op
Zig - unshuffleList - 1000000 indices	34.746 ms/op

by benchmarkbot/action

[philknows]

Just for additional context for when Gemini fails to create a summary:

Short answer: There isn’t a published, exhaustive “unsupported file types” list for the GitHub integration, but Gemini Code Assist’s PR summarization focuses on source-code diffs and Markdown; PRs made up only of non-code assets (for example, media/binaries or office documents) commonly trigger the “file types not supported” message

Typical triggers for “file types not supported”
• PRs that only change media or binary assets (for example, images, audio, or video) are not indexed by Code Customization and often won’t produce a summary.
• PRs that only contain office documents or similar formats (for example, DOCX/PDF) are outside common code-review scope, and Gemini APIs have shown unsupported MIME errors for DOCX in some contexts, which aligns with this limitation.
• PRs without actual source-code diffs (for example, only large generated artifacts) can fail to elicit a summary because the GitHub app targets modified portions of the code.

[wemeetagain]

lets try it out and we can revert if its sus

[philknows]

Going to note that we may not notice much a difference for a large PR like #17, but should be judged on smaller incremental improvements we make to state-transition-z and see how it performs there.