This PR adds additional tests to assert policy_exists functionality.

)

Tooling needs this to serialize as a hex, instead of a number.

Closes #1533

same as #1304 but for
`eth_fillTransaction`

this is not ideal as it does not yet lookup the pool, but should work
for most of the cases

Migrates `tempo.ts/viem` to `viem/tempo`.

Co-authored-by: Jennifer <jenpaff0@gmail.com>

<p align=center><img width=600
src="https://github.com/user-attachments/assets/f45ec0b9-c2f3-4f7f-9634-e4e81678a78d"
/>

Co-authored-by: Jennifer <jenpaff0@gmail.com>

We need to fill the nonce first because with 2d nonces it affects the
gas estimate

Currently renders in the results when searching

<img width="817" height="333" alt="image"
src="https://github.com/user-attachments/assets/7c507d96-5160-4dfb-81a9-a798da6c786f"
/>

and is visible here: https://docs.tempo.xyz/guide/_template#replace-me

Co-authored-by: Jennifer <jenpaff0@gmail.com>

right now when we short-circuit due to zero spending we don't set
`evm.nonce_2d_gas` properly

### Motivation
Developers will be prompting LLMs to build X on Tempo and point them to
pages at docs.tempo.xyz

Observation: LLMs and coding agents vary in whether they'll naturally
discover an llms.txt file. Claude Code and Amp only look at page content
and don't look for an llms.txt on the site unless prompted.
Additionally, the page fetch tools that agents use generally parse HTML
-> .md; headers, tags, etc will be dropped in this process

Hypothesis: models that are aware of an llms.txt file (effectively a
map) and retrieve it have a higher likelihood of completing their build
on Tempo. Hence we should have an explicit pointer to llms.txt for agent
discovery. It's also useful for devs to know that it exists so that they
can e.g. use it to build a build on Tempo skill

### Change
Adds a pointer to llms.txt in the footer on all pages

<img width="3178" height="2468" alt="CleanShot 2025-12-18 at 18 37
20@2x"
src="https://github.com/user-attachments/assets/a90106f2-a373-4e9a-bd26-2e975bdaa5d7"
/>

Co-authored-by: Steven Truong <struong@users.noreply.github.com>
Co-authored-by: Jennifer <jenpaff0@gmail.com>