refactor(engine): clean up a handful of empty raw json blobs we don't need anymore

[mrkaye97]

Description

Building on the work from last week / this week - removing some instances of []byte("{}") that we can drop now by just getting rid of the input opt on the various write paths

Type of change

• Refactor (non-breaking changes to code which doesn't change any behaviour)

Checklist

Changes have been:

• Tested (unit, integration, or manually with steps specified)
• Linted and formatted
• Documented (where applicable)
• Added to CHANGELOG (where applicable) -- see Keep a Changelog

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Project	Deployment	Actions	Updated (UTC)
hatchet-docs	Ready	Preview, Comment	Jul 22, 2026 5:29pm

[github-actions]

⚠️ Optional test failure: The load-online-migrate job failed on this PR. This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[github-actions]

Benchmark results

goos: linux
goarch: amd64
pkg: github.com/hatchet-dev/hatchet/pkg/scheduling/v1
cpu: AMD Ryzen 9 7950X3D 16-Core Processor          
                                         │ /tmp/old.txt │            /tmp/new.txt            │
                                         │    sec/op    │    sec/op     vs base              │
RateLimiter-8                              48.84µ ± 15%   48.42µ ± 11%       ~ (p=0.818 n=6)
Scheduler_Replenish_DenseSharedActions-8   14.06m ±  4%   13.96m ±  2%       ~ (p=0.240 n=6)
geomean                                    828.8µ         822.3µ        -0.79%

                                         │ /tmp/old.txt │            /tmp/new.txt            │
                                         │     B/op     │     B/op      vs base              │
RateLimiter-8                              137.7Ki ± 0%   137.7Ki ± 0%       ~ (p=0.727 n=6)
Scheduler_Replenish_DenseSharedActions-8   11.69Mi ± 0%   11.69Mi ± 0%       ~ (p=0.394 n=6)
geomean                                    1.254Mi        1.254Mi       +0.00%

                                         │ /tmp/old.txt │            /tmp/new.txt             │
                                         │  allocs/op   │  allocs/op   vs base                │
RateLimiter-8                               1.022k ± 0%   1.022k ± 0%       ~ (p=1.000 n=6) ¹
Scheduler_Replenish_DenseSharedActions-8    17.52k ± 0%   17.53k ± 0%       ~ (p=0.232 n=6)
geomean                                     4.232k        4.232k       +0.00%
¹ all samples are equal

_{Compared against main (935328b)}

[github-actions]

⚠️ Optional test failure: The load-online-migrate job failed on this PR. This check is non-mandatory and does not block merging, but may be worth investigating. View logs