feat(libSceWebBrowserDialog): implement sceWebBrowserDialogSetCookie

[Saalik]

What

Implements sceWebBrowserDialogSetCookie, the last unimplemented export of libSceWebBrowserDialog, replacing the NID-only stub:

• the signature changes from no arguments to one pointer param, from SharpProspero's sceWebBrowserDialogSetCookie(WebBrowserDialogSetCookieParam*) binding in WebBrowserDialog.cs
• guards follow the rest of the library: COMMON_DIALOG_ERROR_NOT_INITIALIZED before sceWebBrowserDialogInitialize, COMMON_DIALOG_ERROR_ARG_NULL for a null param
• the param is accepted and discarded, as no browser session exists to store the cookie — the same silent-stub shape as the other dialogs, now listed in TechnicalDebt.md
• TechnicalDebt.md also drops WebBrowserDialog from the unknown-signature entry, since the signature is now sourced

Tested

• extended guest_web_browser_dialog: SetCookie before Initialize returns NOT_INITIALIZED; a null param after Initialize returns ARG_NULL; a param is accepted after Initialize and after Open (any initialized state); builds and passes on Linux
• Not tested on a title

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed in TechnicalDebt
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• AI-assisted: yes

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Written with AI assistance (Cline). The SharpProspero layout was fetched and verified against the linked source; the semantics follow the other silent dialogs and the disclosure lives in TechnicalDebt.md.