Clickable links, full-width terminal and exact page history

- OSC 8 hyperlinks and plain URLs are clickable on the screen and in the
  page history. Links to a section of the current page scroll there,
  others open in a new tab. Links show their target on hover and invert
  in their own color, like the page's links.
- The terminal fills the page column (the fit addon kept room for a
  hidden scrollbar).
- Lines in the page history sit exactly on the terminal's cell grid,
  also for wide and fallback-font characters, and no longer wrap.
- The first command is sent as soon as the shell's line editor is ready,
  instead of guessing from a pause in its output.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -9,7 +9,7 @@
         "@noble/ciphers": "^2.4.0",
         "@noble/curves": "^2.4.0",
         "@noble/hashes": "^2.4.0",
-        "@xterm/addon-fit": "^0.11.0",
+        "@xterm/addon-web-links": "^0.12.0",
         "@xterm/xterm": "^6.0.0",
         "astro": "^7.4.2"
       }
@@ -1526,10 +1526,10 @@
       "integrity": "sha512-1mEZtMKPM09vDmQt5y7YvmN2+DFTP7Tg0EWXdic8/C6VRnpb33e4ghisCIE3WZjsE2N8mf+QV1Zqh7ZFYLWInQ==",
       "license": "ISC"
     },
-    "node_modules/@xterm/addon-fit": {
-      "version": "0.11.0",
-      "resolved": "https://registry.npmjs.org/@xterm/addon-fit/-/addon-fit-0.11.0.tgz",
-      "integrity": "sha512-jYcgT6xtVYhnhgxh3QgYDnnNMYTcf8ElbxxFzX0IZo+vabQqSPAjC3c1wJrKB5E19VwQei89QCiZZP86DCPF7g==",
+    "node_modules/@xterm/addon-web-links": {
+      "version": "0.12.0",
+      "resolved": "https://registry.npmjs.org/@xterm/addon-web-links/-/addon-web-links-0.12.0.tgz",
+      "integrity": "sha512-4Smom3RPyVp7ZMYOYDoC/9eGJJJqYhnPLGGqJ6wOBfB8VxPViJNSKdgRYb8NpaM6YSelEKbA2SStD7lGyqaobw==",
       "license": "MIT"
     },
     "node_modules/@xterm/xterm": {