Support run multiple pipelines in one execution - #89

* Update dependencies, tooling and workflows, add Analyze pipeline

GitHub Actions move to their latest majors (checkout v7, setup-dotnet v6,
pages v5, configure-aws-credentials v6, pulumi v7, NuGet/login v1.2.0).
The duplicate setup-dotnet step in the deploy job is gone, global.json
already pins the SDK.

The msbuild AnalyzeSolution target in Directory.Solution.targets is
replaced by an Analyze pipeline in build.fsx. It resolves the analyzer
package paths through `dotnet msbuild -getProperty`, so the versions live
only in Directory.Packages.props, and it reads the project list from the
solution so the tests, lambda and online tool are analyzed too. PR CI
calls the pipeline. build.fsx gains a shebang and stays on Fun.Build
1.1.16: 1.1.17 runs the default pipeline on `--help` instead of printing
the pipeline list (slaveOftime/Fun.Build#89).

NuGet packages go to their latest stable versions. FCS 43.12.400 pins
FSharp.Core 10.1.400. Ionide.KeepAChangelog.Tasks 0.3.3 requires
bracketed version headings, so CHANGELOG.md is rewritten to
`## [x.y.z] - date`. Pulumi still pins OpenTelemetry 1.9.0, which NuGet
rejects as NU1902, so Telplin.Deploy references the patched 1.18.0
directly. Feliz.UseElmish 5 made `init _` ambiguous, so it takes unit.

The online tool moves to Fable 5: vite-plugin-fable 0.3.1 ships a
prebuilt daemon, so the trustedDependencies entry is gone, Vite 8 and
plugin-react 6 are its peers, Fable.Core 5 / Feliz 3 follow the new
Fable.AST, and Fable.React 10 (React 19 bindings) with react 19 on npm.
The lambda swaps Thoth.Json.Net for Thoth.Json.System.Text.Json.

dotnet tools: fantomas 8.0.0-alpha-026, amazon.lambda.tools 7.0.0,
fsdocs-tool 22.1.0, fsharp-analyzers 0.37.2. Sources reformatted.

Eight tests fail on the new FCS and Fantomas.Core signature output and
still need to be addressed.

* Move to Fantomas 8, fix tests for FCS 43.12, replace Argu with own CLI

Fantomas.Core 8.0.0-alpha-026 changes the Oak: TypeNameNode.Identifier
is a Type rather than an IdentListNode, and Range.Zero is deprecated in
favour of Range.range0. The default multiline bracket style is now
aligned, so the record expectations follow.

FCS 43.12 prints a property whose accessors differ in accessibility as
one member with per-accessor accessibility (`with private get, set`)
instead of one member per accessor. The split introduced for #52 now
accepts a single member and keeps the two-member path for older text.
The remaining expectations follow the new printing: `#seq<'a>` for
flexible types, explicit type parameters on inline SRTP bindings, and
`'T: null` for the constraint an `isNull` check infers.

`nested tuples should no longer be named` is ignored until
dotnet/fsharp#20397 is fixed: 43.11 and later drop the parentheses
around a nested tuple argument when a sibling argument is named, which
prints a different type.

The console application no longer uses Argu. A hand written parser,
help page and theme replace it, in the style of the Fantomas one: the
page lists examples, flags with wrapped descriptions, what an input is,
and links, coloured in the gold of the website when standard out is a
terminal that can show it (NO_COLOR and TERM=dumb are honoured). Flag
names are unchanged. An unknown flag is answered with the closest one,
and complaints go to standard error with an exit code of 1. --version
prints the packed version.

* Release 0.12.0

* Add link to changelog