Remove ReScript support from the analyzer

[cristianoc]

Draft — not for merging yet. Branched off master as requested, so it does not depend on #210/#211.

Removes ReScript from the analyzer itself. #210 covers the docs half of #209; this is the code half.

The pathless flags were already broken for OCaml users

Without a -*-cmt root, processCmtFiles took its None branch → Paths.setReScriptProjectRoot walked up looking for bsconfig.json → then read lib/bs/.sourcedirs.json, a BuckleScript build layout. In a dune project:

$ reanalyze.exe -dce
Error: cannot find project root containing bsconfig.json.
Fatal error: exception File "src/Paths.ml", line 23: Assertion failed

Reanalyze.ml:223 (if !analysisKindSet = false then setConfig ()) made that the default when no flag was passed, and -noalloc had no -cmt variant at all, so it hit the same crash. This removes a path that could only fail in the supported use, not working functionality.

CLI change (the one reviewable decision)

-all, -dce, -exception, -termination and -config are gone. The -*-cmt forms taking a root path are now the only ones, -noalloc becomes -noalloc-cmt, and running with no analysis selected errors instead of silently falling into the bsconfig reader:

$ reanalyze.exe
Error: no analysis selected. Pass one of -all-cmt, -dce-cmt, -exception-cmt,
-termination-cmt with the root path containing the .cmt files.
$ echo $?
1

The alternative was renaming so -dce itself takes the root, keeping -dce-cmt as a deprecated alias. I went with the smaller change because the README, npm test and every example already invoke the -cmt forms — but say the word and I'll switch.

What was deleted (−1,325 / +56)

Target	Before	After
src/ext/ (vendored ReScript JSON parser)	703 lines	deleted
src/vendor/Json.ml	303 lines	18
src/Paths.ml	182 lines	20
src/ExnLib.ml	260 lines	180

Both vendored JSON parsers were reachable only from Paths.ml's bsconfig reader. Json.escape stays — Log_.ml needs it for -json output, which is the one non-ReScript consumer of that module. RunConfig loses projectRoot and bsbProjectRoot, which collapses Suppress.checkPrefix (its projectRoot = "" branch was already the only one the cmt path took).

ExnLib drops the Belt models (~30 table entries covering both Belt.X and Belt_X spellings), Js.Json, and the bs-json decoders, leaving the standard library and Yojson.Basic — which is what EXCEPTION.md documents after #210. Exn loses decodeError and jsExnError; assertFailure stays, since Assert_failure is a real OCaml exception.

Reports now suggest OCaml syntax

@raises(A) → [@raises A], and multiple exceptions print as a tuple rather than a ReScript array:

before:  and is not annotated with @raises([A, B])
after:   and is not annotated with [@raises (A, B)]

Both forms were checked against the analyzer's own parser, so the suggestion is now copy-pasteable. This also fixes the -json emitAnnotate payload that editors insert. Updates examples/deadcode/src/exception.txt.

Verification

dune build clean, npm test green (deadcode, termination, and regression examples). Manually exercised the new error path, -exception-cmt on a scratch project for both the single and tuple suggestion, and confirmed the DCE writer was already emitting correct OCaml ([@@dead "..."]).

Not included

create-release.sh and Dockerfile still tar reanalyze.native out of src/lib/bs/native, a BuckleScript-era path that cannot exist in this tree; dist/ ships a stale prebuilt binary and scripts/download_dist.js serves an npm package CI no longer builds. That is release machinery rather than analysis, so it belongs in its own PR.

#197 should be closed — it adds rescript.json support to the Paths.ml code this PR deletes.

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