Make every clickable control look clickable, in two shared styles (closes #375)

Many controls were plain coloured text with no sign they could be clicked: Edit, Activate, Deactivate, Delete, Replay, Resubmit, both Add controls and the copy control beside each entrypoint URL. Every clickable control is now a real button or link in one of two shared styles: the buttons in input.css, now with a pointer cursor, and btn-small, a small bordered secondary action in style.css, which the layout now loads. The site name, the footer links and each webhook list card show at rest that they open something, with focus states. The copy control shows "Copied" after a click. Rows on the webhook page and in the event log wrap at phone width. The browser test covers the copy control.

Model: opus-5-5

README.md

@@ -1326,15 +1326,16 @@ A browser test in `internal/server` loads the webhook page and the event log
 under the real policy and checks that: both add forms stay hidden until Add is
 clicked; choosing Slack in the add target form leaves the HTTP fields out of
 what it submits, also after leaving the page and going back to it, when the
-browser restores the choice; an event expands and collapses, and so do a
-delivery's attempts inside it; and at phone width the menu button opens and
-closes the mobile menu. It also fails if the browser reports a console warning
-or error, an uncaught exception, or anything the policy refused. `make check`
-and the image build lint it but do not run it, and `make test` leaves it out
-(its file is built only with the `browser` build tag). Run it with
-`make test-browser` after changing `templates/` or `static/js/`: that builds
-`Dockerfile.browser`, which runs the test in a digest-pinned headless browser
-image, so the host needs no browser.
+browser restores the choice; the Copy button beside an entrypoint URL reads
+"Copied" once clicked; an event expands and collapses, and so do a delivery's
+attempts inside it; and at phone width the menu button opens and closes the
+mobile menu. It also fails if the browser reports a console warning or error,
+an uncaught exception, or anything the policy refused. `make check` and the
+image build lint it but do not run it, and `make test` leaves it out (its file
+is built only with the `browser` build tag). Run it with `make test-browser`
+after changing `templates/` or `static/js/`: that builds `Dockerfile.browser`,
+which runs the test in a digest-pinned headless browser image, so the host
+needs no browser.
 
 The package's tarball is committed as `3p/alpinejs-csp-3.14.9.tgz`, byte for
 byte as the npm registry publishes it. It is a dependency, not this repo's build
@@ -3026,7 +3027,7 @@ webhooker/
 │   ├── static.go              # //go:embed directive
 │   ├── css/input.css          # Tailwind input, source for tailwind.css (make css)
 │   ├── css/tailwind.css       # Generated stylesheet the pages load
-│   ├── css/style.css          # Older hand-written stylesheet, no longer loaded
+│   ├── css/style.css          # Hand-written, loaded after tailwind.css: btn-small, the pointer cursor for input.css's buttons, the webhook list cards' focus outline
 │   ├── js/app.js              # Copy-to-clipboard, and the Alpine.js components
 │   └── js/alpine.min.js       # Alpine.js CSP build, extracted from 3p/ by make assets, not committed
 ├── templates/                 # Go HTML templates (base, login, sources, etc.)