feat(webpublish): publish the log as a web page or CSV, with FTP upload

Settings -> Web publishing. Renders the last N QSOs with the columns the
operator picks, writes the file locally, and optionally uploads it by FTP or
explicit FTPS.

Local write FIRST, upload second, always. A network failure then leaves a good
file on disk that can be published another way, instead of a truncated one on
the server. The local write itself goes to a temp file and renames over the
target, so a reader — or a syncing client — never sees a half-written page.

The HTML page is fully self-contained: inline CSS, inline sort script, no font,
no CDN, no external request at all. It has to work on hosting that blocks
third-party requests, and a page about someone's hobby should not report its
readers to anyone.

Columns are a curated set, not "every ADIF field". This is published to the
public: RST and QSL status belong on it, the operator's home address does not.

Two triggers, both debounced through one path: a QSO is logged, or the optional
timer fires. Fifteen seconds of coalescing means a run of contacts produces one
upload rather than one per QSO, and nobody reading a web page can tell the
difference.

The config is one JSON blob under a single settings key, and that key is marked
sensitive: the FTP password lives inside it, so the whole blob is encrypted at
rest with the others. A locked vault reads back empty, which correctly reads as
"not configured" — publishing must not run with a password it cannot decrypt.

go.sum

@@ -25,6 +25,8 @@ github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs
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+github.com/jlaffaye/ftp v0.2.2 h1:JwjrXCAIjN9ZYrF1/8qlmHFXDteh9MHYaiEIh/Oqtd8=
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 github.com/labstack/echo/v4 v4.13.3 h1:pwhpCPrTl5qry5HRdM5FwdXnhXSLSY+WE+YQSeCaafY=
 github.com/labstack/echo/v4 v4.13.3/go.mod h1:o90YNEeQWjDozo584l7AwhJMHN0bOC4tAfg+Xox9q5g=
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@@ -64,8 +66,8 @@ github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
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-github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
-github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/tkrajina/go-reflector v0.5.8 h1:yPADHrwmUbMq4RGEyaOUpz2H90sRsETNVpjzo3DLVQQ=
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