deploy: docs: overhaul readme (googleapis#2821)

## Description

> Should include a concise description of the changes (bug or feature),
it's
> impact, along with a summary of the solution

## PR Checklist

> Thank you for opening a Pull Request! Before submitting your PR, there
are a
> few things you can do to make sure it goes smoothly:

- [ ] Make sure you reviewed

[CONTRIBUTING.md](https://github.com/googleapis/genai-toolbox/blob/main/CONTRIBUTING.md)
- [ ] Make sure to open an issue as a

[bug/issue](https://github.com/googleapis/genai-toolbox/issues/new/choose)
  before writing your code! That way we can discuss the change, evaluate
  designs, and agree on the general idea
- [ ] Ensure the tests and linter pass
- [ ] Code coverage does not decrease (if any source code was changed)
- [ ] Appropriate docs were updated (if necessary)
- [ ] Make sure to add `!` if this involve a breaking change

🛠️ Fixes #<issue_number_goes_here>

---------

Co-authored-by: Kurtis Van Gent <31518063+kurtisvg@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Yuan Teoh <45984206+Yuan325@users.noreply.github.com> a68cb22

Author: 3 people

dev/documentation/getting-started/local_quickstart/index.html

@@ -516,7 +516,7 @@
 </span></span><span class=line><span class=cl>gcloud services <span class=nb>enable</span> aiplatform.googleapis.com
 </span></span></code></pre></div></li></ol><h2 id=step-1-set-up-your-database>Step 1: Set up your database</h2><p>In this section, we will create a database, insert some data that needs to be
 accessed by our agent, and create a database user for Toolbox to connect with.</p><ol><li><p>Connect to postgres using the <code>psql</code> command:</p><div class=highlight><pre tabindex=0 class=chroma><code class=language-bash data-lang=bash><span class=line><span class=cl>psql -h 127.0.0.1 -U postgres
-</span></span></code></pre></div><p>Here, <code>postgres</code> denotes the default postgres superuser.</p><style type=text/css>.notice{--title-color:#fff;--title-background-color:#6be;--content-color:#444;--content-background-color:#e7f2fa}.notice.info{--title-background-color:#fb7;--content-background-color:#fec}.notice.tip{--title-background-color:#5a5;--content-background-color:#efe}.notice.warning{--title-background-color:#c33;--content-background-color:#fee}@media(prefers-color-scheme:dark){.notice{--title-color:#fff;--title-background-color:#069;--content-color:#ddd;--content-background-color:#023}.notice.info{--title-background-color:#a50;--content-background-color:#420}.notice.tip{--title-background-color:#363;--content-background-color:#121}.notice.warning{--title-background-color:#800;--content-background-color:#400}}body.dark .notice{--title-color:#fff;--title-background-color:#069;--content-color:#ddd;--content-background-color:#023}body.dark .notice.info{--title-background-color:#a50;--content-background-color:#420}body.dark .notice.tip{--title-background-color:#363;--content-background-color:#121}body.dark .notice.warning{--title-background-color:#800;--content-background-color:#400}.notice{padding:18px;line-height:24px;margin-bottom:24px;border-radius:4px;color:var(--content-color);background:var(--content-background-color)}.notice p:last-child{margin-bottom:0}.notice-title{margin:-18px -18px 12px;padding:4px 18px;border-radius:4px 4px 0 0;font-weight:700;color:var(--title-color);background:var(--title-background-color)}.icon-notice{display:inline-flex;align-self:center;margin-right:8px}.icon-notice img,.icon-notice svg{height:1em;width:1em;fill:currentColor}.icon-notice img,.icon-notice.baseline svg{top:.125em;position:relative}</style><div class="notice info"><p class=notice-title><span class="icon-notice baseline"><svg viewBox="92 59.5 300 300"><path d="M292 303.25V272c0-3.516-2.734-6.25-6.25-6.25H267v-1e2c0-3.516-2.734-6.25-6.25-6.25h-62.5c-3.516.0-6.25 2.734-6.25 6.25V197c0 3.516 2.734 6.25 6.25 6.25H217v62.5h-18.75c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h87.5c3.516.0 6.25-2.734 6.25-6.25zm-25-175V97c0-3.516-2.734-6.25-6.25-6.25h-37.5c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h37.5c3.516.0 6.25-2.734 6.25-6.25zm125 81.25c0 82.813-67.188 150-150 150-82.813.0-150-67.188-150-150 0-82.813 67.188-150 150-150 82.813.0 150 67.188 150 150z"/></svg>
+</span></span></code></pre></div><p>Here, <code>postgres</code> denotes the default postgres superuser.</p><div class="notice info"><p class=notice-title><span class="icon-notice baseline"><svg viewBox="92 59.5 300 300"><path d="M292 303.25V272c0-3.516-2.734-6.25-6.25-6.25H267v-1e2c0-3.516-2.734-6.25-6.25-6.25h-62.5c-3.516.0-6.25 2.734-6.25 6.25V197c0 3.516 2.734 6.25 6.25 6.25H217v62.5h-18.75c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h87.5c3.516.0 6.25-2.734 6.25-6.25zm-25-175V97c0-3.516-2.734-6.25-6.25-6.25h-37.5c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h37.5c3.516.0 6.25-2.734 6.25-6.25zm125 81.25c0 82.813-67.188 150-150 150-82.813.0-150-67.188-150-150 0-82.813 67.188-150 150-150 82.813.0 150 67.188 150 150z"/></svg>
 </span>Info</p><h4 id=having-trouble-connecting><strong>Having trouble connecting?</strong></h4><ul><li><strong>Password Prompt:</strong> If you are prompted for a password for the <code>postgres</code>
 user and do not know it (or a blank password doesn&rsquo;t work), your PostgreSQL
 installation might require a password or a different authentication method.</li><li><strong><code>FATAL: role "postgres" does not exist</code>:</strong> This error means the default

dev/documentation/getting-started/local_quickstart_go/index.html

@@ -514,7 +514,7 @@
 </span></span><span class=line><span class=cl>gcloud services <span class=nb>enable</span> aiplatform.googleapis.com
 </span></span></code></pre></div></li></ol><h2 id=step-1-set-up-your-database>Step 1: Set up your database</h2><p>In this section, we will create a database, insert some data that needs to be
 accessed by our agent, and create a database user for Toolbox to connect with.</p><ol><li><p>Connect to postgres using the <code>psql</code> command:</p><div class=highlight><pre tabindex=0 class=chroma><code class=language-bash data-lang=bash><span class=line><span class=cl>psql -h 127.0.0.1 -U postgres
-</span></span></code></pre></div><p>Here, <code>postgres</code> denotes the default postgres superuser.</p><div class="notice info"><p class=notice-title><span class="icon-notice baseline"><svg viewBox="92 59.5 300 300"><path d="M292 303.25V272c0-3.516-2.734-6.25-6.25-6.25H267v-1e2c0-3.516-2.734-6.25-6.25-6.25h-62.5c-3.516.0-6.25 2.734-6.25 6.25V197c0 3.516 2.734 6.25 6.25 6.25H217v62.5h-18.75c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h87.5c3.516.0 6.25-2.734 6.25-6.25zm-25-175V97c0-3.516-2.734-6.25-6.25-6.25h-37.5c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h37.5c3.516.0 6.25-2.734 6.25-6.25zm125 81.25c0 82.813-67.188 150-150 150-82.813.0-150-67.188-150-150 0-82.813 67.188-150 150-150 82.813.0 150 67.188 150 150z"/></svg>
+</span></span></code></pre></div><p>Here, <code>postgres</code> denotes the default postgres superuser.</p><style type=text/css>.notice{--title-color:#fff;--title-background-color:#6be;--content-color:#444;--content-background-color:#e7f2fa}.notice.info{--title-background-color:#fb7;--content-background-color:#fec}.notice.tip{--title-background-color:#5a5;--content-background-color:#efe}.notice.warning{--title-background-color:#c33;--content-background-color:#fee}@media(prefers-color-scheme:dark){.notice{--title-color:#fff;--title-background-color:#069;--content-color:#ddd;--content-background-color:#023}.notice.info{--title-background-color:#a50;--content-background-color:#420}.notice.tip{--title-background-color:#363;--content-background-color:#121}.notice.warning{--title-background-color:#800;--content-background-color:#400}}body.dark .notice{--title-color:#fff;--title-background-color:#069;--content-color:#ddd;--content-background-color:#023}body.dark .notice.info{--title-background-color:#a50;--content-background-color:#420}body.dark .notice.tip{--title-background-color:#363;--content-background-color:#121}body.dark .notice.warning{--title-background-color:#800;--content-background-color:#400}.notice{padding:18px;line-height:24px;margin-bottom:24px;border-radius:4px;color:var(--content-color);background:var(--content-background-color)}.notice p:last-child{margin-bottom:0}.notice-title{margin:-18px -18px 12px;padding:4px 18px;border-radius:4px 4px 0 0;font-weight:700;color:var(--title-color);background:var(--title-background-color)}.icon-notice{display:inline-flex;align-self:center;margin-right:8px}.icon-notice img,.icon-notice svg{height:1em;width:1em;fill:currentColor}.icon-notice img,.icon-notice.baseline svg{top:.125em;position:relative}</style><div class="notice info"><p class=notice-title><span class="icon-notice baseline"><svg viewBox="92 59.5 300 300"><path d="M292 303.25V272c0-3.516-2.734-6.25-6.25-6.25H267v-1e2c0-3.516-2.734-6.25-6.25-6.25h-62.5c-3.516.0-6.25 2.734-6.25 6.25V197c0 3.516 2.734 6.25 6.25 6.25H217v62.5h-18.75c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h87.5c3.516.0 6.25-2.734 6.25-6.25zm-25-175V97c0-3.516-2.734-6.25-6.25-6.25h-37.5c-3.516.0-6.25 2.734-6.25 6.25v31.25c0 3.516 2.734 6.25 6.25 6.25h37.5c3.516.0 6.25-2.734 6.25-6.25zm125 81.25c0 82.813-67.188 150-150 150-82.813.0-150-67.188-150-150 0-82.813 67.188-150 150-150 82.813.0 150 67.188 150 150z"/></svg>
 </span>Info</p><h4 id=having-trouble-connecting><strong>Having trouble connecting?</strong></h4><ul><li><strong>Password Prompt:</strong> If you are prompted for a password for the <code>postgres</code>
 user and do not know it (or a blank password doesn&rsquo;t work), your PostgreSQL
 installation might require a password or a different authentication method.</li><li><strong><code>FATAL: role "postgres" does not exist</code>:</strong> This error means the default