[ ide-mode ] return formatted version string for :interpret ":version" command

[keram]

Note:
I acknowledge the AI contributing policy and made the changes primarily on own but I did consulted AI and been guided by it to make this change correctly.

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Previously, the IDE command :version (via interpret) reused ShowVersion and returned a structured S-expression containing semantic version components and commit hash.

As idris-mode expects for output of :interpret command to be always a string. This leads to bad user experience on commands that return S-expression. See: idris-hackers/idris-mode#661 and idris-hackers/idris-mode#662

This introduces a dedicated VersionSExp constructor in IDEResult and updates process Version to return the raw version value directly.
The IDE mode now distinguishes between:

• REPL (VersionIs x) -> structured AVersion (unchanged)
• VersionSExp x -> formatted string via showVersion

As a result, :version in IDE interpret mode now produces a human-readable string (e.g. "0.8.0-") instead of a structured tuple.

Before:

idris2 --ide-mode
000018(:protocol-version 2 1)
(:version 1)
00002a(:return (:ok ((0 8 0) ("19a3f4ec0"))) 1)
((:interpret ":version") 2)
00002a(:return (:ok ((0 8 0) ("19a3f4ec0"))) 2)

After:

$ idris2 --ide-mode
000018(:protocol-version 2 1)
(:version 1)
00002a(:return (:ok ((0 8 0) ("ed55358b6"))) 1)
((:interpret ":version") 2)
000024(:return (:ok "0.8.0-ed55358b6") 2)

Next steps:

Update :opts command in similar way.

((:interpret ":opts") 3)
00009b(:return (:ok ((:show-implicits :False) ...)) 3) ;; should be string
((:get-options) 3)
00009b(:return (:ok ((:show-implicits :False) .. (:editor "vim"))) 3) ;; stay same

Description

Self-check

• This is my first time contributing, I've carefully read CONTRIBUTING.md
  and I've updated CONTRIBUTORS with my name.
• If this is a fix, user-facing change, a compiler change, or a new paper
  implementation, I have updated CHANGELOG_NEXT.md
• I confirm that this contribution did not involve GenerativeAI nor Large Language Models.