Add options to git show completion spec

Add comprehensive options to the git show subcommand in git.json,
complementing the existing branch/tag/commit generators. Options include
format, diff output, display, notes, and tab expansion settings.

Closes APP-3486

Co-Authored-By: Oz <oz-agent@warp.dev>

Author: lucieleblanc

command-signatures/json/git.json

@@ -6213,6 +6213,181 @@
         {
             "name": "show",
             "description": "Show various types of objects",
+            "options": [
+                {
+                    "name": "--format",
+                    "description": "Pretty-print the contents of the commit logs in a given format",
+                    "requiresSeparator": true,
+                    "args": {
+                        "name": "format",
+                        "suggestions": [
+                            {
+                                "name": "oneline",
+                                "description": "<hash> <title-line>"
+                            },
+                            {
+                                "name": "short",
+                                "description": "Short format"
+                            },
+                            {
+                                "name": "medium",
+                                "description": "Medium format"
+                            },
+                            {
+                                "name": "full",
+                                "description": "Full format"
+                            },
+                            {
+                                "name": "fuller",
+                                "description": "Fuller format"
+                            },
+                            {
+                                "name": "reference",
+                                "description": "Reference format"
+                            },
+                            {
+                                "name": "email",
+                                "description": "Email format"
+                            },
+                            {
+                                "name": "raw",
+                                "description": "Show the entire commit exactly as stored"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "name": "--abbrev-commit",
+                    "description": "Show only a partial hexadecimal commit object name"
+                },
+                {
+                    "name": "--no-abbrev-commit",
+                    "description": "Show the full 40-byte hexadecimal commit object name"
+                },
+                {
+                    "name": "--oneline",
+                    "description": "Shorthand for \"--pretty=oneline --abbrev-commit\""
+                },
+                {
+                    "name": "--encoding",
+                    "description": "Re-code the commit log message in the encoding",
+                    "requiresSeparator": true,
+                    "args": {
+                        "name": "encoding"
+                    }
+                },
+                {
+                    "name": "--expand-tabs",
+                    "description": "Perform a tab expansion in the log message"
+                },
+                {
+                    "name": "--no-expand-tabs",
+                    "description": "Do not perform a tab expansion in the log message"
+                },
+                {
+                    "name": "--notes",
+                    "description": "Show the notes that annotate the commit",
+                    "isRepeatable": true,
+                    "args": {
+                        "name": "ref",
+                        "isOptional": true
+                    }
+                },
+                {
+                    "name": "--no-notes",
+                    "description": "Do not show notes"
+                },
+                {
+                    "name": [
+                        "-s",
+                        "--no-patch"
+                    ],
+                    "description": "Suppress diff output"
+                },
+                {
+                    "name": "--show-signature",
+                    "description": "Check the validity of a signed commit object"
+                },
+                {
+                    "name": "--stat",
+                    "description": "Generate a diffstat"
+                },
+                {
+                    "name": "--numstat",
+                    "description": "Show number of added and deleted lines in decimal notation"
+                },
+                {
+                    "name": "--shortstat",
+                    "description": "Output only the last line of the --stat format"
+                },
+                {
+                    "name": "--name-only",
+                    "description": "Show only names of changed files"
+                },
+                {
+                    "name": "--name-status",
+                    "description": "Show names and status of changed files"
+                },
+                {
+                    "name": [
+                        "-p",
+                        "-u",
+                        "--patch"
+                    ],
+                    "description": "Generate patch"
+                },
+                {
+                    "name": [
+                        "-q",
+                        "--quiet"
+                    ],
+                    "description": "Suppress diff output"
+                },
+                {
+                    "name": "--raw",
+                    "description": "Show the raw diff format"
+                },
+                {
+                    "name": "--color",
+                    "description": "Show colored diff",
+                    "args": {
+                        "name": "when",
+                        "isOptional": true,
+                        "suggestions": [
+                            "always",
+                            "never",
+                            "auto"
+                        ]
+                    }
+                },
+                {
+                    "name": "--no-color",
+                    "description": "Turn off colored diff"
+                },
+                {
+                    "name": "--diff-filter",
+                    "description": "Select only files that are Added (A), Copied (C), Deleted (D), Modified (M), Renamed (R), have their type changed (T), are Unmerged (U), are Unknown (X), or have had their pairing Broken (B)",
+                    "requiresSeparator": true,
+                    "args": {
+                        "name": "filter",
+                        "suggestions": [
+                            { "name": "A", "description": "Added" },
+                            { "name": "C", "description": "Copied" },
+                            { "name": "D", "description": "Deleted" },
+                            { "name": "M", "description": "Modified" },
+                            { "name": "R", "description": "Renamed" },
+                            { "name": "T", "description": "Type changed" },
+                            { "name": "U", "description": "Unmerged" },
+                            { "name": "X", "description": "Unknown" },
+                            { "name": "B", "description": "Broken" }
+                        ]
+                    }
+                },
+                {
+                    "name": "--",
+                    "description": "Separates paths from options for disambiguation purposes"
+                }
+            ],
             "args": {
                 "name": "object",
                 "isVariadic": true,