fix(broadcast): rasterize email logo + flow icons to PNG for client compatibility

Gmail and Outlook strip inline <svg> and don't reliably render <img src=*.svg>,
so the header wordmark and the four flow-mark icons could render blank/broken.
Swap to hosted PNGs (logo.png + readme-*-mark.png, transparent, hi-res) with
alt text, matching the v0.5/v0.6 broadcast pattern. Remove the unused SVGs.

Author: waleedlatif1

apps/sim/emails/broadcasts/july-1.html

@@ -62,12 +62,7 @@
                 <tr>
                   <td align="left" style="vertical-align:middle;">
                     <a href="https://sim.ai" style="color:#1A1A1A;text-decoration:none;" target="_blank">
-                      <svg viewBox="0 0 441 212" width="37" height="18" fill="#1A1A1A" role="img" aria-label="Sim" style="display:block;width:37px;height:18px;">
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-                        <path d="M232.8 212H202.125L202.125 49.7551H229.537V77.3879C232.8 68.3361 239.109 60.6617 247.811 54.7009C256.731 48.5194 267.5 45.4286 280.118 45.4286C294.259 45.4286 306.007 49.292 315.362 57.0188C324.717 64.746 330.809 75.0115 333.637 87.8165H328.089C330.265 75.0115 336.247 64.746 346.037 57.0188C355.827 49.292 367.902 45.4286 382.26 45.4286C400.535 45.4286 414.893 50.8374 425.336 61.6551C435.779 72.4727 441 87.2644 441 106.03V212H410.977V113.647C410.977 100.842 407.714 91.0175 401.188 84.174C394.879 77.1091 386.285 73.5768 375.407 73.5768C367.793 73.5768 361.048 75.3432 355.174 78.8754C349.518 82.1867 345.058 87.044 341.795 93.4462C338.532 99.8484 336.9 107.355 336.9 115.965V212H306.551V113.316C306.551 100.511 303.396 90.7966 297.088 84.174C290.778 77.33 282.185 73.908 271.307 73.908C263.693 73.908 256.949 75.6743 251.075 79.2066C245.419 82.5178 240.958 87.3751 237.695 93.7773C234.432 99.9591 232.8 107.355 232.8 115.965V212Z" />
-                        <path d="M184.831 20.551C184.831 31.901 175.636 41.102 164.294 41.102C152.952 41.102 143.757 31.901 143.757 20.551C143.757 9.20101 152.952 0 164.294 0C175.636 0 184.831 9.20101 184.831 20.551Z" />
-                        <path d="M179.426 212H149.162V49.7551C153.756 51.9119 158.884 53.1178 164.294 53.1178C169.704 53.1178 174.833 51.9119 179.426 49.7551V212Z" />
-                      </svg>
+                      <img src="https://sim.ai/email/broadcast/july-1/logo.png" width="37" alt="Sim" style="display:block;width:37px;height:auto;" border="0">
                     </a>
                   </td>
                   <td align="right" style="vertical-align:middle;">
@@ -152,19 +147,19 @@ <h1 style="margin:0;color:#1A1A1A;font-family:'Season Sans',-apple-system,'SF Pr
                     <table width="100%" cellspacing="0" cellpadding="0" border="0" role="presentation">
                       <tr>
                         <td class="mobile-stack" align="center" width="25%" style="color:#1A1A1A;font-family:'Season Sans',-apple-system,'SF Pro Display','SF Pro Text','Helvetica',sans-serif;font-size:13px;font-weight:430;line-height:18px;padding-right:12px;text-align:center;vertical-align:top;">
-                          <img src="https://sim.ai/email/broadcast/july-1/readme-integrate-mark.svg" width="82" height="82" alt="Integrate" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
+                          <img src="https://sim.ai/email/broadcast/july-1/readme-integrate-mark.png" width="82" height="82" alt="Integrate" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
                           <p style="margin:0;color:#1A1A1A;font-size:13px;line-height:18px;">Integrate</p>
                         </td>
                         <td class="mobile-stack" align="center" width="25%" style="color:#1A1A1A;font-family:'Season Sans',-apple-system,'SF Pro Display','SF Pro Text','Helvetica',sans-serif;font-size:13px;font-weight:430;line-height:18px;padding-right:12px;text-align:center;vertical-align:top;">
-                          <img src="https://sim.ai/email/broadcast/july-1/readme-ingest-mark.svg" width="82" height="82" alt="Context" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
+                          <img src="https://sim.ai/email/broadcast/july-1/readme-ingest-mark.png" width="82" height="82" alt="Context" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
                           <p style="margin:0;color:#1A1A1A;font-size:13px;line-height:18px;">Context</p>
                         </td>
                         <td class="mobile-stack" align="center" width="25%" style="color:#1A1A1A;font-family:'Season Sans',-apple-system,'SF Pro Display','SF Pro Text','Helvetica',sans-serif;font-size:13px;font-weight:430;line-height:18px;padding-right:12px;text-align:center;vertical-align:top;">
-                          <img src="https://sim.ai/email/broadcast/july-1/readme-build-mark.svg" width="82" height="82" alt="Build" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
+                          <img src="https://sim.ai/email/broadcast/july-1/readme-build-mark.png" width="82" height="82" alt="Build" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
                           <p style="margin:0;color:#1A1A1A;font-size:13px;line-height:18px;">Build</p>
                         </td>
                         <td class="mobile-stack mobile-stack-last" align="center" width="25%" style="color:#1A1A1A;font-family:'Season Sans',-apple-system,'SF Pro Display','SF Pro Text','Helvetica',sans-serif;font-size:13px;font-weight:430;line-height:18px;text-align:center;vertical-align:top;">
-                          <img src="https://sim.ai/email/broadcast/july-1/readme-monitor-mark.svg" width="82" height="82" alt="Monitor" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
+                          <img src="https://sim.ai/email/broadcast/july-1/readme-monitor-mark.png" width="82" height="82" alt="Monitor" style="display:block;width:82px;height:82px;margin:0 auto 8px;" border="0">
                           <p style="margin:0;color:#1A1A1A;font-size:13px;line-height:18px;">Monitor</p>
                         </td>
                       </tr>