Feat/support jsignpdf 3

[YvesCesar]

Related issue #52

Updates the wrapper to the current stable JSignPdf (3.1.0) and keeps every password out of the command line.

CLI differences between 2.3 and 3.1

Change	What it required here
Passwords can be read from stdin since 3.0.0: --enable-stdin-passwords plus - as the option value, read one line each in the fixed order -ksp, -kp, -opwd, -upwd, -tscp, -tsp	signing moved from exec() to proc_open(), writing the passwords to stdin
The fat jar was dropped in 3.1; the ZIP ships a lib/ directory	start from the classpath (com.intoolswetrust.jsignpdf.Bootstrap), keeping -jar as a fallback for 3.0.x
Default hash algorithm is now SHA-256	documented; it needs at least a PDF-1.6
The CLI appends the signature by default; --overwrite was added and -a kept as a no-op	documented; example/index.php now passes --overwrite
--version output and the Finished: Signature succesfully created. message	unchanged, so the parsing was kept as it was

What changed

• Every value reaching the shell goes through escapeshellarg(): the java binary, the jar or classpath, the PDF, -ksf and -d.

• No password is passed as an argument any more. Besides setPassword(), the key, owner, user and TSA passwords have their own setters and are sent through stdin:

  $param->setTsaPassword('tsa password');

Passing them to setJSignParameters() as a list works too — the value is taken out of the command line just the same.

• setJSignParameters() accepts a list of options and values, which the package escapes.
• The installer downloads to a staging directory and replaces the previous install instead of merging into it, so upgrades don't leave a stale jar behind.
• The default download URL is now jsignpdf-3.1.0-minimal.zip.

Compatibility

• JSignPdf 2.x is no longer supported: it has no way to read passwords from stdin. Pointing setJSignPdfDownloadUrl() or setjSignPdfJarPath() at a 2.x release stops working. JSignPdf 3.x needs a Java 21+ runtime.
• Signing a PDF older than 1.6 with the default parameters now fails, because SHA-256 needs PDF-1.6 and the append mode cannot upgrade the PDF version. Use --overwrite or a hash algorithm the PDF version supports.
• The string form of setJSignParameters() is still passed through unparsed, so a password written there does reach the command line. The README points to the setters and to the list form instead.

Testing

• Unit tests for version detection, successful signing, signing errors, paths with spaces and quotes, option values with shell metacharacters, the order of the passwords on stdin, both distribution layouts and the installer upgrade paths.
• A new integration group runs the real JSignPdf — version, signing, visible signature with page and coordinates, explicit hash algorithm, more than one password on stdin, and the pre-1.6 failure. It runs in its own CI job and is excluded from test:unit and from coverage.

[vitormattos]

Excellent work!