style(web): align --link with the accent blue (#4183c4)

`--link` was still the brighter GitHub blue while everything else moved to
Gitea's #4183c4, so links read as a second, slightly different accent. One blue
now.

Contrast on this palette: 4.50:1 on --panel (#161718), 4.14:1 on --bg
(#1e1f20), 3.77:1 on --panel-2 (#22272e) — down from 4.79 / 4.41 / 4.01. Body
links sit on --panel and stay above the 4.5:1 AA threshold; the ones on the
darker surfaces (nav hover, table cells) land between AA-large and AA, as the
rest of this palette's dim text already does.

plans/web-ui-redesign-plan.md

@@ -84,7 +84,7 @@ Legend: `[ ]` todo · `[~]` in progress · `[x]` done · `[!]` blocked
 --color-text-light     #c0c2c7   (dim)
 --color-secondary      #3f4248   (border-ish)
 --color-success-text   #3fb950   --color-error-text #f85149   --color-warning-text #d29922
---color-info-text      #2f81f7
+--color-info-text      #4183c4
 ```
 
 ### Health thresholds (status header + row colors)

src/ci_orchestrator/web/static/app.css

@@ -21,7 +21,7 @@
   --success: #3fb950;
   --danger: #f85149;
   --warn: #d29922;
-  --link: #2f81f7;
+  --link: #4183c4;
   /* Single rounding token, matched to Gitea's `--border-radius` (~4px) so
    * cards, buttons, inputs, code, notices and badges all round identically.
    * The only intentional exception is the gauge/progress track (a pill). */