docs: added design docs for eth_sendRawTransaction fast transaction hash return

[quiet-node]

Description:
This PR introduces a design document detailing additional aspects of the new feature that allows eth_sendRawTransaction to immediately return the transaction hash after passing all prechecks.

Related issue(s):
More aspects and considerations of the feature are highlighted in the ongoing discussion in #3202. Please feel free to share your insights in the thread if you have any.

Fixes #3281

Notes for reviewer:

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[github-actions]

Test Results

 19 files   -  1  244 suites   - 33   31m 48s ⏱️ + 1m 26s
608 tests  -  5  603 ✅ + 3  4 💤 ±0  1 ❌  - 8 
699 runs  +39  694 ✅ +47  4 💤 ±0  1 ❌  - 8 

For more details on these failures, see this check.

Results for commit 82e6bbf. ± Comparison against base commit 3a9b577.

This pull request removes 5 tests.

"before all" hook for "transfers the requested amount" ‑ RPC Server Acceptance Tests Acceptance tests @erc20 Acceptance Tests ERC20 Contract should behave like erc20 transfer from when the token owner is not the zero address when the recipient is not the zero address when the spender has enough allowance when the token owner has enough balance "before all" hook for "transfers the requested amount"
"before all" hook for "transfers the requested amount" ‑ RPC Server Acceptance Tests Acceptance tests @erc20 Acceptance Tests HTS token should behave like erc20 transfer from when the token owner is not the zero address when the recipient is not the zero address when the spender has enough allowance when the token owner has enough balance "before all" hook for "transfers the requested amount"
"before all" hook in "@api-batch-2 RPC Server Acceptance Tests" ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests "before all" hook in "@api-batch-2 RPC Server Acceptance Tests"
"before each" hook for "reverts" ‑ RPC Server Acceptance Tests Acceptance tests @erc20 Acceptance Tests ERC20 Contract should behave like erc20 transfer from when the token owner is not the zero address when the recipient is the zero address "before each" hook for "reverts"
"before each" hook for "reverts" ‑ RPC Server Acceptance Tests Acceptance tests @erc20 Acceptance Tests HTS token should behave like erc20 transfer from when the token owner is not the zero address when the recipient is the zero address "before each" hook for "reverts"

♻️ This comment has been updated with latest results.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[acuarica]

lg

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.89%. Comparing base (3a9b577) to head (82e6bbf).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3282   +/-   ##
=======================================
  Coverage   77.89%   77.89%           
=======================================
  Files          66       66           
  Lines        4470     4470           
  Branches     1003     1003           
=======================================
  Hits         3482     3482           
  Misses        613      613           
  Partials      375      375           

Flag	Coverage Δ
config-service	98.14% <ø> (ø)
relay	78.64% <ø> (ø)
server	83.28% <ø> (ø)
ws-server	36.66% <ø> (ø)

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