implement live-reloading dev server

Squashed commit of the following:

commit 02f077432202af4d633eb2cad81dfdaa6921317f
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 21:09:14 2024 +0200

    builder: only remove output directory if set and in dev mode

commit 47001e01c55fa6e74aafeda04ebc3e4e7c47eba0
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 21:03:37 2024 +0200

    implement live reload on dev server

commit 411ec969f61e4b73439f1c54ea29f75135ecc618
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 20:59:26 2024 +0200

    server: implement graceful shutdown

commit 5400132eb6eb1b638e0b3fd4265f51611c92d473
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 20:41:07 2024 +0200

    add some debug logs

commit 3c9b678197c044603950232d222f501ef74d7873
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 20:39:09 2024 +0200

    prefix log output with executable name

commit 300e24c179e390e9d3f5aeab4471c97f17f1fa64
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Sat Apr 27 20:29:42 2024 +0200

    don't panic inside internal packages, return error instead

commit fe2715d330402ad67fe866471bed89c7238ad2ec
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Fri Apr 26 01:18:29 2024 +0200

    config: use a table to configure CSP headers

commit d012553aaf78a436fa8871830b5d720a9e292d4b
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Thu Apr 25 17:13:39 2024 +0200

    dev: create basic dev server to build and serve from a temporary directory

commit a1d11d3e69650d9b43ca1b1d7b7ccc05a808d5c1
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Thu Apr 25 13:02:22 2024 +0200

    remove unused redirect_other_hostnames config option

commit fd67b19b5c7f76f0c3579e8a05ef20a618e90be7
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Thu Apr 25 12:58:53 2024 +0200

    server: make port a string, which is what go uses

commit c798e8e736c0649008cade337158399470a9099b
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Thu Apr 25 12:58:33 2024 +0200

    config: remove unused port variable

commit f94882b9001f3b0855e26b26b4a84b96e3deb22b
Author: Alan Pearce <alan@alanpearce.eu>
Date:   Thu Apr 25 12:49:10 2024 +0200

    re-organise module layout

1 files changed, 51 insertions, 6 deletions

diff --git a/nix/gomod2nix.toml b/nix/gomod2nix.toml
index 1e2501d..8c6ac1f 100644
--- a/nix/gomod2nix.toml
+++ b/nix/gomod2nix.toml
@@ -17,6 +17,9 @@ schema = 3
   [mod."github.com/andybalholm/cascadia"]
     version = "v1.3.2"
     hash = "sha256-Nc9SkqJO/ecincVcUBFITy24TMmMGj5o0Q8EgdNhrEk="
+  [mod."github.com/antage/eventsource"]
+    version = "v0.0.0-20220422142129-c4aae935d5bd"
+    hash = "sha256-5JLLEwW3L3Mt756q3Qw0TKtrNjQ3VtEsV9S2JfdPHy0="
   [mod."github.com/antchfx/xmlquery"]
     version = "v1.4.0"
     hash = "sha256-ReWP6CPDvvWUd7vY0qIP4qyxvrotXrx9HXbGbeProP4="
@@ -26,30 +29,69 @@ schema = 3
   [mod."github.com/ardanlabs/conf/v3"]
     version = "v3.1.7"
     hash = "sha256-7H53l0JN5Q6hkAgBivVQ8lFd03oNmP1IG8ihzLKm2CQ="
+  [mod."github.com/bep/godartsass"]
+    version = "v1.2.0"
+    hash = "sha256-kkKRFesHX8Yp1+/L7yFeRqltBRlAVKgdSN4d7Lc/uI8="
+  [mod."github.com/bep/godartsass/v2"]
+    version = "v2.0.0"
+    hash = "sha256-ISvlb0UVikyLGPCrkQus//HVgAcgplQDhdIuTrmToRM="
+  [mod."github.com/bep/golibsass"]
+    version = "v1.1.1"
+    hash = "sha256-rQK/w54sh57GtCG8plKbkFxWBZB0+7RLMvOGCV2jvqY="
+  [mod."github.com/cli/safeexec"]
+    version = "v1.0.1"
+    hash = "sha256-74r/MHyMIxDSGA2D862d/OQ3lYLozxoUIRMyL0n03m8="
+  [mod."github.com/crewjam/csp"]
+    version = "v0.0.2"
+    hash = "sha256-4vlGmDdQjPiXmueCV51fJH/hRcG8eqhCi9TENCXjzfA="
   [mod."github.com/deckarep/golang-set/v2"]
     version = "v2.6.0"
     hash = "sha256-ni1XK75Q8iBBmxgoyZTedP4RmrUPzFC4978xB4HKdfs="
+  [mod."github.com/fatih/structtag"]
+    version = "v1.2.0"
+    hash = "sha256-Y2pjiEmMsxfUH8LONU2/f8k1BibOHeLKJmi4uZm/SSU="
+  [mod."github.com/fsnotify/fsnotify"]
+    version = "v1.7.0"
+    hash = "sha256-MdT2rQyQHspPJcx6n9ozkLbsktIOJutOqDuKpNAtoZY="
   [mod."github.com/getsentry/sentry-go"]
     version = "v0.27.0"
     hash = "sha256-PTkTzVNogqFA/5rc6INLY6RxK5uR1AoJFOO+pOPdE7Q="
+  [mod."github.com/gobwas/glob"]
+    version = "v0.2.3"
+    hash = "sha256-hYHMUdwxVkMOjSKjR7UWO0D0juHdI4wL8JEy5plu/Jc="
+  [mod."github.com/gohugoio/hugo"]
+    version = "v0.125.4"
+    hash = "sha256-BHTawZLm/82SXJyGq17pIizqHCG2NJRuqTioKqcu880="
   [mod."github.com/golang/groupcache"]
     version = "v0.0.0-20210331224755-41bb18bfe9da"
     hash = "sha256-7Gs7CS9gEYZkbu5P4hqPGBpeGZWC64VDwraSKFF+VR0="
-  [mod."github.com/kr/pretty"]
-    version = "v0.3.1"
-    hash = "sha256-DlER7XM+xiaLjvebcIPiB12oVNjyZHuJHoRGITzzpKU="
+  [mod."github.com/mattn/go-isatty"]
+    version = "v0.0.20"
+    hash = "sha256-qhw9hWtU5wnyFyuMbKx+7RB8ckQaFQ8D+8GKPkN3HHQ="
+  [mod."github.com/mitchellh/hashstructure"]
+    version = "v1.1.0"
+    hash = "sha256-dNPVpLRsCa2XZHlCRRtkpBVqb8rpHIocpFPNCqZg2EY="
   [mod."github.com/otiai10/copy"]
     version = "v1.14.0"
     hash = "sha256-xsaL1ddkPS544y0Jv7u/INUALBYmYq29ddWvysLXk4A="
+  [mod."github.com/pelletier/go-toml/v2"]
+    version = "v2.2.1"
+    hash = "sha256-gmQ4CTz/MI97D3pYqU7mpxqo8gBTDccQ1Cp0lAMmJUc="
   [mod."github.com/pkg/errors"]
     version = "v0.9.1"
     hash = "sha256-mNfQtcrQmu3sNg/7IwiieKWOgFQOVVe2yXgKBpe/wZw="
-  [mod."github.com/rogpeppe/go-internal"]
-    version = "v1.10.0"
-    hash = "sha256-vR7+d0aoKTuKeTYSgZxsGhH9e5Zvxix3Zrq9SPm5+NQ="
   [mod."github.com/shengyanli1982/law"]
     version = "v0.1.13"
     hash = "sha256-gjXWxWR6XCpOUYKBzPaObw2hPOmkoVtuHd1aMHm/ljA="
+  [mod."github.com/spf13/afero"]
+    version = "v1.11.0"
+    hash = "sha256-+rV3cDZr13N8E0rJ7iHmwsKYKH+EhV+IXBut+JbBiIE="
+  [mod."github.com/spf13/cast"]
+    version = "v1.6.0"
+    hash = "sha256-hxioqRZfXE0AE5099wmn3YG0AZF8Wda2EB4c7zHF6zI="
+  [mod."github.com/tdewolff/parse/v2"]
+    version = "v2.7.13"
+    hash = "sha256-mG6TO8hcXUmi9yKIogrfoDLWE6i6qs4LTjr7mSmqb7M="
   [mod."github.com/yuin/goldmark"]
     version = "v1.7.1"
     hash = "sha256-3EUgwoZRRs2jNBWSbB0DGNmfBvx7CeAgEwyUdaRaeR4="
@@ -65,6 +107,9 @@ schema = 3
   [mod."golang.org/x/text"]
     version = "v0.14.0"
     hash = "sha256-yh3B0tom1RfzQBf1RNmfdNWF1PtiqxV41jW1GVS6JAg="
+  [mod."google.golang.org/protobuf"]
+    version = "v1.33.0"
+    hash = "sha256-cWwQjtUwSIEkAlAadrlxK1PYZXTRrV4NKzt7xDpJgIU="
   [mod."gopkg.in/check.v1"]
     version = "v1.0.0-20201130134442-10cb98267c6c"
     hash = "sha256-VlIpM2r/OD+kkyItn6vW35dyc0rtkJufA93rjFyzncs="