forgit: Add interactive git discard command

Currently, unstaging and reverting uncommitted changes requires
running separate git reset and git checkout commands. This is
error-prone and lacks the interactive file selection that other
forgit commands provide, forcing users to manually specify files or
risk discarding unintended changes.

Add forgit_discard (gdc) command that combines unstaging and
reverting into a single interactive operation. This provides a safer
workflow by showing a preview of changes before discarding and allows
selective file-by-file confirmation, consistent with forgit's design
philosophy of making destructive operations more deliberate.

Signed-off-by: Javier Tia <floss@jetm.me>

Author: jetm

README.md

@@ -144,6 +144,8 @@ If you're having issues after updating, and commands such as `forgit::add` or al
 
 - **Interactive `git reset HEAD <file>` selector** (`grh`)
 
+- **Interactive `git discard` (unstage and revert) selector** (`gdc`)
+
 - **Interactive `git checkout <file>` selector** (`gcf`)
 
 - **Interactive `git checkout <branch>` selector** (`gcb`)
@@ -222,6 +224,7 @@ forgit_diff=gd
 forgit_show=gso
 forgit_add=ga
 forgit_reset_head=grh
+forgit_discard=gdc
 forgit_ignore=gi
 forgit_attributes=gat
 forgit_checkout_file=gcf
@@ -286,6 +289,7 @@ These are passed to the according `git` calls.
 | `gd`     | `FORGIT_DIFF_GIT_OPTS`                                                      |
 | `gso`     | `FORGIT_SHOW_GIT_OPTS`                                                      |
 | `grh`    | `FORGIT_RESET_HEAD_GIT_OPTS`                                                |
+| `gdc`    | `FORGIT_DISCARD_GIT_OPTS`                                                   |
 | `gcf`    | `FORGIT_CHECKOUT_FILE_GIT_OPTS`                                             |
 | `gcb`    | `FORGIT_CHECKOUT_BRANCH_GIT_OPTS`, `FORGIT_CHECKOUT_BRANCH_BRANCH_GIT_OPTS` |
 | `gsw`    | `FORGIT_SWITCH_BRANCH_GIT_OPTS`                                             |
@@ -346,6 +350,7 @@ Customizing fzf options for each command individually is also supported:
 | `gd`     | `FORGIT_DIFF_FZF_OPTS`            |
 | `gso`    | `FORGIT_SHOW_FZF_OPTS`            |
 | `grh`    | `FORGIT_RESET_HEAD_FZF_OPTS`      |
+| `gdc`    | `FORGIT_DISCARD_FZF_OPTS`         |
 | `gcf`    | `FORGIT_CHECKOUT_FILE_FZF_OPTS`   |
 | `gcb`    | `FORGIT_CHECKOUT_BRANCH_FZF_OPTS` |
 | `gsw`    | `FORGIT_SWITCH_BRANCH_FZF_OPTS`   |
@@ -396,6 +401,7 @@ export FORGIT_LOG_FZF_OPTS='
 | `FORGIT_FULLSCREEN_CONTEXT`    | lines of diff context in full-screen mode                                                                                      | 10                                            |
 | `FORGIT_DIR_VIEW`              | command used to preview directories                                                                                            | `tree` if available, otherwise `find`         |
 | `FORGIT_CLEAN_LIST_FILES_OPTS` | arguments passed to `git ls-files` together with `--others` to determine which files are shown when invoking `forgit clean`    |                                               |
+| `FORGIT_DISCARD_CONFIRM`       | Prompt for confirmation before discarding changes                                                                              |                                               |
 
 # 📦 Optional dependencies